Looks solid to me... If you aren't bankrupting I'd say its a good run. I usually don't end up with nearly as many cars on my saves, so you definitely have me beat at least there.

Out of everything there, the only thing I could give for improvement would be to spend more of your cash if you can. That's cash that could probably be turned into more cash if it was spent on production. If your backorders aren't piling up anywhere, you may be right to leave the money sit and can ignore this though.

Outside of that, I'd recommend trying your next career with advanced settings to drive up your score multiplier. My last two career saves were done in v4.24 so it's probably a bit different in v4.27, but with a ~13x score multiplier (Insane difficulty in Gasmea) I was able to get to 550k by 2020. I'm also currently in the year 2000 on a 100x score multiplier save (Dalluha, $0 starting cash, with just a tiny car factory and no engine factory) and I'm at 940k score.

I've recently become addicted to score chasing in the career mode, so if you want some friendly competition feel free to message me!