Expert in the cryptocurrency market will say to you the time you can have a great profiting time in the market is the time during the halving or a little after it. At that time more investors enter in for buy and that keep the price steadily up until the current ATH is over taken then some people start to pull out, this is what I notice on my own. This halving last year can repeat this history and investors are waiting for a moment they will come in and take advantage of the market.
The halving two years ago can indeed be taken as a reference for the next halving, but I will only take a few references from the previous halving because the difference will be clear even if it is slight so I will only see references from a small portion of the halvings that have occurred in the past . But if you want to fully believe that's fine too because the next halving does exist and the possibility for Bitcoin to make ATH again is also very possible as long as the big influence is there.