How does premier's elo actually work?

I know this sub probably gets this question all the time but I figured I'll ask anyway. I come from valorant and have started playing premier with usually 1 or 2 of my friends, (we are all around 4-5k elo). for some reason specifically my elo is really messed up or something and i consistently get into games with people around 8-10k with or without my friends. to be clear, i perform terribly in these "high" elo games and every time i lose a ton more rank than i normally do when playing with my skill level. (ex. usually im around -100 on loss but in these high elo games its like -250?)

So my question is, why does the game match me into much better players even when my performance is consistently bad against them? and why do i lose MORE elo when i lose games against players double my rank when logically i should be less punished for losing a game that is much harder to win?

thanks in advance for any responses. sorry if this was wordy