Definitely Rimworld, it will tax the hell out of that 3060 /s

In all seriousness though, congrats, and those are all great games and I love all of them, you seem to have similar interests to me. I can't really recommend any particular one over another. That said, when I get a new computer my first choice for a new game is typically something that is a fun, lighthearted, colourful visual feast that I can immerse myself in. In the past for me that has been something like Subnautica, ARK Survival Evolved, but of course this changes over time. Given that Subnautica 2 Early Access just released and I've already worked my way through it, I would consider recommending that. Or if you're not into Early Access in general or Subnautica in particular, perhaps something like Satisfactory might also properly start to show off your new hardware. Star Rupture is another interesting option. If you don't really want to get into first person stuff and stick to the grand strategy side, Stellaris is another fun one although a lot of the DLC is pretty crap lately. And I'm always a sucker for Age of Wonders series, with 4 being the most recent entry.