^ If you go spot, you won't lose everything.
So don't worry, and be a happy hodler.
Use your funds wisely, and remember about Bitcoin whenever there is a possibility to invest.

all the buying strategy that are commonly used by investors are all good as long as you use them the right way and that they are suitable to the kind of investor that you are. as good as the DCA method might be, there might be individual that it might not work out for maybe based on the nature of their finance. it doesn't mean that the approach is bad but just that based on the peculiarity of your finance, you might need to buy using the lump sum or some other approach that might just be peculiar to your case. at the end, whatever time you buy that gives you the desirable comfort as an investor is your best buying time.

the DCA looks like the preferable choice of most investors including myself and the reason why people prefer it is that it looks like the combination of all the other approach, and it helps you to continue investing regardless of your financial status and the current price of bitcoin and by so doing, you get to constantly buy with the amount you have at a time and do so constantly without a form of interruption due to the different market condition you might experience along the time you remained invested.

When you say "if things go badly..." I am interested in knowing what can possibly go badly with buying and holding bitcoin. I know people always make this statement of investing what one is willing to lose yet we have not seen any holder lose money by holding, so I get confused understanding where the idea of one losing money in bitcoin is coming from when we are already advocating for long term holding.  The only time I know people lose money in bitcoin is when they put money they cannot leave in bitcoin for long hence they are forced to sell at lose when the market is correcting or does not go in their direction within their period of endurance. Apart from this case, people don't lose money in bitcoin.

I meant that no one really knows what will happen in the future. Yes, based on the experience of past years, long-term investment in Bitcoin guarantees profit. But that doesn't mean you can be 100% sure about it. I just wanted to warn that anything could happen, and we need to be prepared for anything. That said, I completely agree with you.

^ Today is the day because it's the best, just like the rest 

I believe while following Dollar Cost Average (DCA) it's essential not to miss any valuable/beneficial opportunities to capitalize on market movements, regardless of the direction, such opportunities allows you to utilize every market dip. But if the currency to invest is Bitcoin then it's don't really matter to use DCA or any other investment plan. because it always call you for vital opportunity to invest after a period of time, while in long term hold every investor make money even when if they come with lum sum or straight investment strategy. But the main things is when it come to rather than spot trading then always invest such amount which are you capable to lose

The best time is not just today - but whenever you have the capital and opportunity. You have to have a strategy if you want to buy bitcoin so that you don't just stick to only buying on dips - meaning you can buy at any time as long as you have the right strategy. You could even buy at $110K - then you buy at $90K, then you buy at $80K, that would put your average buying price at $93K. That's why you need to be strategic when buying instead of just focusing on the price.

It's true that buying when the price drops can make you buy more coins - but it takes time to get a correction of 5% to 15% in a day. Without a strong reason behind the correction then you have to wait that long.

As an old Chinese proverb goes: The best time to plant a tree was 20 years ago. The second best time is now.
The most profitable time for entry might have passed long time ago, but that's not to say you can't make profit in the current day.

You have to be wary of the post-halving 4-year cycles though. Buying now has a high chance of yielding you a double digit % return in a near future, but if you're here for a long run, I'd either go with a DCA, wait for the post-cycle dip, or create a strategy combining these two.

If there is an opportunity and capital, keep buying and collecting our BTC. I think even if we delay and delay waiting for another correction, the possibility is not impossible that the price will move up quickly. Indeed, it is difficult to get the price we want the most, but if it is close to the range we planned, like poster above, it can be handled quickly. Everything needs to be done when the time comes.

A good proverb indeed.
And I agree - long-run is the best way for BTC. Surely it will be a long road, but it will be a rewarding one for sure, with any amount of BTC that you would accumulate.