welp, I got the piece of broken SIM tray out of my old phone, but it still won't read my SIM, I guess it was a good call to replace the device because if I get this fixed it'll take quite a while (and probably not be worth it, considering the price of a used LG G6)
still, I'd like to get this fixed because the phone is fine, it's literally just the ports that are failing, the parts are less than 10€ it's just a pain to take apart and put back together