Lag when playing LoL when OBS is running?

I'm about to lose my mind here. I've tried so many things, but no matter what I do it feels like if I try to stream LoL (I use OBS), I experience mild to severe lag.

It also doesn't even have to be while ACTUALLY streaming, just with OBS up. I'm worried it's my computer (a 2020 PC), but people have said if I can stream Cyberpunk with no issues, it shouldn't be the computer.

I'm going to leave a list of what I've already tried. Any tips/suggestions/insights much appreciated!

1. Running OBS as administrator

2. Making sure OBS is updated

3. Changing in-game specs to 60 FPS

4. Enabling "low-spec mode" in-game

5. Taking out "game capture" in OBS and switching to "window capture"

6. Using "windows 10" as the "method" in "window capture"

Changing OBS Output settings under "streaming" and "pre-set" to "P3" and then to "P1"

7. Taking out "window capture" and switching to "game capture" AND un-checking the "anti-cheating" hook thing

8. Setting the CBR (bit rate) in OBS lower, between 6-8k

9. And of course, turning off anything running in the background like discord, wallpaper enginge, etc.

HELP. I really want to be able to stream League. :/