I have been racing using RR3 since 2015 so I'd say I was a reasonably proficient but not good like a lot of the users who post. I was able to complete each update version (get all the cars) however, as Firemonkeys increased the difficulty over time I needed to farm more to keep up with the GC spend. When v7.3.0 (Bugatti Update May 19) was released I found Speedrush Season 4 just too difficult (and with expensive upgrades) I restored back and then took the decision to leave the app as many racers do when they've had enough.
I returned just after V8.0 had been released and pretty much picked up where I left off although I missed out on a stack of cars. I started to watch YouTube videos created by the gamechanger community and this helped a lot getting through the challenges however, I started to run the WTTT and OLMP which got me an extra 18 + 8 GC which helps. I farm just enough each update (Lemans 10 lapper every other day and M$250,000 with 3 daily F1 endurance races) to end with around 1000 GC - giving plenty for something new and expensive in the next update (as well as slowly clearing the backlog of missed cars).
Now to the crunch - early April I stopped using TC assist which did take a little getting used to however, my WTTT moved from (E-D) to (D-C) with FU car. The lap times on Lemans also improved as did the F1 somewhat. In preparation of v9.4 release I decided to try and lose SA too so turned it off last Wednesday. Learning braking points doesn't take long and by Monday I could run the Lemans 10 lap without running off track although the F1 races are more challenging.
Yesterday I managed to complete Club Day: Divo in 2 hours 10 mins (all 3's) and reading about the challenges that a lot of racers have then switching off BA might just get you over the line, it isn't too onerous and you will pick it up quickly.