Yay I sort of got something to work lol. I wasn't able to get the brightnessctl to work at all but I was unaware of the "software manager" thing so I went there and found a rather mediocre app called "Change PC Brightness" that has a little button in the corner that I have to click and scroll and I can adjust the screen brightness that way. I guess it gets the job done so I'm pretty stoked on that despite it's rather user-unfriendliness tbh haha.
I have heard about the Redshift thing and was unable to get it to work via the link you sent me and same thing when I went into the Software Manager. I guess I'll just have to order a bluelight blocking sticker like my old laptop has.
Not 100% successful in terms of satisfaction to be perfectly honest, but the mere fact that I got SOMETHING to work and that I can now adjust my screen brightness would be considered a success indeed.
Thanks for your help!