I just thought about it recently when I played against someone who is level 63 and checked our past game: I am 21-0 against them. Another lvl 62 player, I am beating 44-7, to a point they sometimes surrender turn 1 or 2 if they deem they don't have better starts. A lvl 57 player I am currently 30-1 against. On the other hand, there is one lvl 57 player against whom I am 7-10, they may be the only player to have a winning record against me with double digit 1v1 games played together. All four players I only play on the same template.
Do you have similar instances of players of comparable strength/level to yours, against whom you've played many times, and for some reason, you win or lose more than 80% of the times against them?

This is not uncommom, because level has only very little correlation with skill in this game :)

I've won 19/19 games against this player https://www.warzone.com/Profile?p=22145090104&u=Andrija_1. All games are strategic 1v1 from RT QM.

I have just beaten "scottiedee21" who I had blocked for a long time I think, and they tried to taunt me in the chat, therefore I checked: I am 22-1 against them. They are lvl 64 and have decent stats despite terrible boot with 13 out of the last 100 games.
I must admit I was happy to win and see our record after a player I had blocklisted tried to taunt me for no reason.

Level just shows how many points you got. Someone with 1.000 games and 1.000 wins will be on the same level as someone with 100.000 games and 1.000 wins. (We assume here that they play the same gamemode and roughly same level opponents)

So you're literally just bragging about beating up some random guys nobody knows