I didn't have those problems when I did it. In fact, it was the other way around for me. Electrum didn't connect to electrum.labrie.ca when I pasted the port as well. The orb in the bottom right remained red. So I went into the network settings and deleted the port part. I got connected to the server then and Electrum added the port settings on its own.

Buying a new computer or upgrading to a newer OS? If you don't mind me asking, why is that exactly? What's preventing you to perform the upgrade?

Wow, you are amazing! I often visit and check mempool.space. I noticed that transaction fees were regularly started with 0.20 sat/vByte and 0.30 sat/vByte. At first I thought that it was a glitch because I've seen the same before on Mempool and posted here, where I got told that it was a mistake because it's impossible to send transactions with lower than 1 sat/vByte fee. Now I see that what I noticed recently was not a glitch but reality and your tutorials are great for each wallet. I'm gonna test it on both, Electrum and Sparrow. Now it will be 5 times cheaper to consolidate my UTXOs with 0.20 sat/vByte.

Electrum will probably be easier for most people especially since we know now at least two servers that have been configured properly to support below 1 sat/vByte transactions, plus there is mempool.space for broadcasting a previously signed transaction. With Sparrow Wallet, it's a bit more challenging. If you have your own node, you can update its settings and connect to it via Sparrow. But can Sparrow connect to all public Electrum nodes? I never tested it.

Bitcoin Core was the first client that supported below 1 sat/vByte transactions but since I don't use it and have no experience with it, I can't comment on the steps to get it to work either. Your node and software settings have to be configured to relay such transactions. Read the last 5 pages of this thread starting with this post. You will find info how to edit your Bitcoin Core's config file there.

It probably won't be confirmed or relayed by many other nodes. What it will do is make your transaction become the lowest possible priority for miners. Right now there are 45-50vMB of unconfirmed transactions sitting in mempools according to data from Jochen Hoenicke. A transaction paying 0.001 sat/vB would be at the bottom of that list unless you can get a miner to include it in a block they mine before its time comes. And the majority of all other new unconfirmed transactions would pay more than you.

The average person would just be wasting time and end up with a stuck transaction that needs to be RBF-ed. Not even all miners have agreed to include 0.1 sat/vByte transactions in their blocks, so I wouldn't go lower than that right now.

Confirmed? Sure, miners won't take that dust, if they have transactions with bigger fees. But relayed? Let's see:
There are a lot of nodes, which declare to accept free transactions. Of course, a lot of them are probably not mining anything, but only relaying it.

However, if free, or low-fee transactions would be widely relayed by a lot of nodes, and they would be open for modifications, then guess what: users could use that kind of communication channel, to batch a lot of low-fee transactions into some bigger fee transactions, and then broadcast it to the miners.

But of course, allowing free transactions unconditionally means, that if all of these node operators are vulnerable to some DoS attacks. Unless of course they put some protections, and after accepting for example N free transactions, they stop accepting next ones, or they require a minimal Proof of Work inside some transaction, or something like that. But this is hard to detect, you can only see declared fees, it is hard to discover, if all of these nodes are really vulnerable, or if they just declare to be.

Note that RBF rules depends on fees. And guess what happens, if allowed fees are set to zero, and how RBF works in that case.

Why not, if there are a lot of nodes, accepting such transactions?

Here's my overview:
I didn't expect so many nodes to accept zero-fee transactions. I guess these settings were created before miners started accepting 0.1 sat/vbyte transactions.
The last 2 in my list are interesting: maybe they're trying to reduce RAM usage?

I've set my node to accept a minimum of 0.1 sat/vbyte. Miners are the gate keepers to blocks, so I don't see the point of going lower if miners ignore it.

Realistically, who's going to do that if there's no GUI-wallet that can easily create such transactions? If the average (or even advanged) user has to manually do this, the risk of making mistakes isn't worth the few cents saved on transaction fees.

Your client would then have to be connected to some of those nodes because if it isn't and you are only connected to nodes that won't relay such transactions, your low-fee transaction won't propagate and spread around the network.

But will mining nodes of Foundry, AntPool, F2Pool, AntPool, etc., etc., accept those transactions? If not, then it doesn't really matter what some nodes accept.