Now that's what I call a lucky winner. Didn't think the odds were THAT small actually (not that 1 in over a million is small) but I suppose this already pays out his cost, wonder how what his profit margin's been across all those 262 blocks found?

Anyone knows what the record is for solo block found with the most improbability (or lowest odds)?

A mining pool is referred to a server where miners share the same work and get paid for their contribution. In CK pool (regardless of the name) the work is not shared, so it can't be called a mining pool. In a mining pool, all miners are working on the same exact block with the same exact coinbase.
In CK pool each miner is doing its own work on its own block with their own unique coinbase. CK pool is just providing a node and "header production" service!

Are you sure about this?
I heard that the newer versions of stratum allow each miner some kind of flexibiliity

You are referring to the BetterHash and Stratum V2 protocols that give the hashers more control over what transactions go into the blocks.

Regardless, whether or not the hashers are working on the same block with the same coinbase is irrelevant. The basis of a pool is that if anyone in the pool finds a block, everyone in the pool shares the reward. If that is not the case, then it can't be considered to be a pool.

With the current exchange rates, it is like $270,000. I am not sure how much he/she might have spent on the mining equipment, but it should be lower by a magnitude of 100x-1,000x. So this reward is like hitting a lottery jackpot. LOL.. how this miner would have felt after coming to know about the reward? BTW, a few other factors might have contributed to his luck. China hashpower is completely wiped out due to hostile government action. And then there is the ongoing unrest in Kazakhstan, which has knocked out another 15% of the global mining contribution.

As I am not a technical person about mining, could you please point those “facts wrong” and tell me the widely accepted concept of pools vs solo mining?
I just want to understand, no sarcasm.

It is mathematically expected for solo miners to occasionally find blocks. Like someone winning the Powerball, even if it is expected that someone will eventually win, people still like to talk about the Powerball winner.

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While I am sure the person using the ~$11k miner is happy they were able to get a ~$262k payout, it is -EV for a miner to mine if the expected number of blocks they will find every frequency that the difficulty increases is less than 1.

For example, if a miner expects to find 0.2 blocks every two weeks, and for the difficulty to increase by 10% every two weeks, if they mine via a pool, they will get approximately 0.2 blocks worth of revenue for the current two week period, and if they are solo mining, they will expect to not receive any revenue during that two week period. Since the difficulty is increasing, the solo miner would not expect to find a block until after the difficulty changes 7 times. After that, they would not expect to find another block for over a year.

I already did.

The definition of solo mining is someone who isn't sharing/pooling the "work". Whether or not they run their own node isn't changing that.
However, you can and should criticize that these miners are not independent since they don't run their own node and rely on a third party.

Perhaps a better analogy would be tip pooling in a restaurant.

Scenario 1 (early days of solo mining):
Restaurant only accepts cash.  All waitstaff are tipped with cash.  Tips are paid directly from the customer to the person waiting on their table. Waitstaff keep their own tips and don't share them with any of the other waitstaff No pooling is happening. Lots of people are working, and sometimes they get a tip from a customer, but they don't share those tips with any of the others that are also working.

Scenario 2 (early days of mining pools):
Restaurant switches to exclusively accepting credit cards. Since restaurant handles payment processing, they end up with all the tips. Restaurant pools the tips together and then distributes them to the waitstaff on payday based on how much time each spent working during that pay period, regardless of how much tips any single employee did or didn't bring in. Now the entire restaurant is acting like a single pool. Everyone gets a share of the tips, even if the. customers that they themselves waited on never tipped.

Scenario 3 (ckpool):
Restaurant still exclusively accepting credit card, and still handling payment processing. Instead of distributing the tips based on how much time each employee spent working during that period, the restaurant keeps track of exactly which tips were paid for which employee.  On payday each employee receives ONLY the tips that were paid by customers whose tables they waited on. Restaurant keeps 2% of the tips from each employee to pay for handling the payment processing and distribution of funds. Like Scenario 1, you only get the tips that were paid by your customers, but like Scenario 2, all funds and payment processing are being managed by the restaurant.

Would you call Scenario 3 "tip pooling"?  One answer might be, no, because each employee only got the tips that were paid to them from the customers, and didn't share in the tips that any other employee received.  Another answer might be, yes, because the restaurant handled the payment processing and kept a bit of the tips for themselves.  This is where the confusion arises. Since ckpool is creating the blockheaders, and is keeping a piece of the earnings for themselves, some people are saying it is not "solo mining".  On the other hand, since the miner receives only the rewards from the blocks that they themselves find the solution for (and don't participate in any rewards from any blocks that anyone else finds the solution for), most people are calling this "solo mining".

As pooya87 has pointed out, the widely accepted definition of "solo mining" is someone that is not pooling the work. If the only way you get paid is when you yourself (or the equipment that you are running) solve a block, then it's generally understood that you are solo mining (regardless of who is creating the block headers that you are working on).  If you get paid for every share of work that you complete (regardless of whether you ever find a block solution yourself), then it's generally understood that you are not solo mining.

In ckpool, as a solo miner, your odds of solving a block, and of therefore getting paid at all, can be calculated based entirely on the ratio of the hash power that you personally have control over vs. the current target difficulty.  This is exactly the same as it is for a solo miner that is creating their own blockheaders.  If you participate in a pool where you are not solo mining, then the odds of a block being solved by the pool can be calculated based on the sum of all the hash power contributed by all the pool participants vs. the current target difficulty.  You therefore get paid much more frequently (albeit a much smaller reward since all the participants in the pool are sharing that reward based on the amount of hash power each contributed).