Upgrade?

I've just got a pc from my brother and I'm new to the whole pc stuff and I want to know what to upgrade and when. My pc has a nvidia geforce RTX 2060 super, 16 gb ram , and a i7-7700k. I don't have a lot of money and I don't play massive games ( fallout, minecraft) so I want to know if it even needs an upgrade and if if it does what to get at a reasonable price.

I won't ever need the best stuff the most I'll do is play stellaris.