I'm really, REALLY bad

and I'm not sure what to even do about it. I understand the skill ceiling is lower with a controller. I can't afford a wheel right now, so I accept that I can only do so well. What I don't understand (and yes I'm aware it's technically a skill issue) is why I can do so well in free practice and then once in the actual race I am GARBAGE. Sometimes it's not my fault, people in sport mode just do not seem to care about their SR half the time. But if I'm in dead last with no other racers near me, how come I never get even close to the same lap times I got in practice? Idk I know this probably isn't productive and it's a pointless post but I gotta get it off my chest somehow.

I guess just to ask an actual question, does anyone have any tips for improving my racing skills on controller? Again, I can't afford a wheel etc. right now, so please refrain from telling me stuff like "just get a wheel" or whatever.

EDIT: I just wanna thank this community for actually trying to be helpful rather than immediately being super toxic.