Advice getting back into Umamusume Pretty Derby

I stopped playing around 3 or 4 months ago because it felt like I wasn't progressing well, I started the game only being able to make C rank runners then slowly progressed to B and I just got stuck being able to make B+ or just A rank runners and I couldn't go higher than that, does anyone got advice how to get back into the game.

Like what is best career to make strong runners and what strategies do i need to apply to for different umas and their running styles and preferred tracks, what support cards should I be on the look out to get (i only use carats to scout support card and only summon for runners if there are free scouting available)

What are the best ways to train umas for quest that rely on certain skills or stats to be present at the end of a run.

Sorry if this is alot to ask for I just recently reinstalled the game after getting an AD about the 1.5 anniversary and thought it would be a good idea to get back into the game during the anniversary celebration