I’d recommend checking out Planetary Annihilation, Planetary Annihilation:Titans, Supreme Commander 1/2 and their mods

Exactly, all my favourite games, and ones with a small but dedicated modding community, are how they are largely because of player creations.

Project Zomboid, Barotrauma, Kerbal Space Program, they are all relatively inexpensive, amazing heartfelt games made by small studios (RIP ksp2)