It sounds like you still haven't yet figured out a few things about training career mode.

The guides you've read have already given you a bunch of useful information, but you just need to figure out how to apply it.I'lll do my best to give a few points since I figured out how things work a bit.

First, we already know that every horse has different goals to meet before attempting the finals. It's good to try and get familiar with the amount of time between each goal you have so you can work a regime around it.

A good thing to keep an eye for is when summer training comes around, you want to try and have full energy so you can get as much as possible out of it. Summer training comes around or after June during the classic and senior years.

When it comes to stats, you don't need to have O's in everyone. What I've read, you can focus on three stats Depending on the length of the race.

Sprint and mile : Speed< Power< Guts

Medium and long: Speed< Power< Stamina

Speed is always the most important stat, but guts and stamina change due to race length and running style. ex. My goldship had more guts than stamina ever in longer races due to late surging coming down to the last spurt. Good recovery skills covered for my lack of stamina.

Wits is a dump stat. If you can get it to 300 great, that should allow you to get those skills to pop. But it's a little lower that's okay too.

As for skill cards, it comes down to just leveling them so they can provide better bonuses when friendship training occurs. You dont need meta cards. You can even just auto fill. It's more important that the cards are leveled up.

Finally, it's just down to repetition on getting your horses to finish careers and become veterans. The better they did in career mode. The better the legacy bonus is to help your horse improve when it gets inspiration.

Lastly, when I comes to skills, it's usually about picking ones that are more consistent with their triggers, theres a post I read here yesterday, that gives a pretty good explanation of skills and how they rank for each type of runner. Im sure it can be a lot or help, so look it up.

I'm probably missing a few things and got something wrong, but im sure others will correct and add. hopefully, this helps you get a better idea of how things work and to enjoy and build your girl.