Oh hell yeah, I stopped playing on lichess because my opponents would do this then ask for a takeback. I do it myself almost... gamely... is that a word
Am I The Only Beginner Who Does This?
yeah but it gets annoying and sometimes they say mouseslip and I cant tell, although it wasn't really a big deal looking back

(The answer is probably "Yes" but here goes....)
I cannot believe how many times -- the INSTANT -- I make a move, I realize, "Oops! THAT move would have been way better.
I suppose this happens less frequently after ... (What?) ... 6 months? ... a year?
You're not the only one. When I make a move and then realize that something else is better and what I did was a blunder. Happens a lot in my games, even in daily games! (Around 1300 in Rapid and around 1200 in Blitz and Bullet, and 1000 in Daily)

(The answer is probably "Yes" but here goes....)
I cannot believe how many times -- the INSTANT -- I make a move, I realize, "Oops! THAT move would have been way better.
I suppose this happens less frequently after ... (What?) ... 6 months? ... a year?
For me it's more often that the instant I make a move, I realize that I just blundered and I've lost my queen. And another move later I realize that it's mate in 3.

(The answer is probably "Yes" but here goes....)
I cannot believe how many times -- the INSTANT -- I make a move, I realize, "Oops! THAT move would have been way better.
I suppose this happens less frequently after ... (What?) ... 6 months? ... a year?
It happened to me when i started to play chess, the best solution is to ignore the time and think what the oponent is going to do in his situation, after that, review like 2 times the move that you're going to do.

(The answer is probably "Yes" but here goes....)
I cannot believe how many times -- the INSTANT -- I make a move, I realize, "Oops! THAT move would have been way better.
I suppose this happens less frequently after ... (What?) ... 6 months? ... a year?
Yup sometimes do that to but not many times
I am also beginner and I always lose at chess. :_( :_( :_( :_( :.( ;) ;) ;)
I looked at some of your games. (I'm WAY below you in rating) but IMO, you play way too fast. You frequently have more than five minutes remaining in your ten minute Rapid games.
I suspect you'd make much better moves if you took more time. (Some of the best advice I got as a newcomer was actually(!) to lose more games by timing-out.) I still stink, but I don't blunder-after-blunder as much.