I always disable it. Having everything using the same exact colour palette is boring/homogenized. The themed icons are even worse, simultaneously killing iconography art and making it much more difficult to differentiate between apps in the app drawer quickly.
It’s a half-assed project for some high level designer at Google to claim impact.
I wish the UI were actually, meaningfully customizable, but alas…
Can’t you just get a new launcher? That’s day one of getting a new phone for me