I had the same experience. I even decided to build my base up to 75 science/minute after the first rocket launch, but once I hit that and was finding myself just crafting modules to increase productivity/efficiency to do infinite research with no real end in sight, it was all grind and no fun for me.

I could have decided to make a real megabase, push for the highest spm my PC can handle, and optimize to the end of time, but at some point I'd have to return to the real world.

End game is all boring alien culling for more mining expansions just to get diminishing returns on infinite research you don't really need anyways. I'm not really a fan of the colonial extractivist themes, and that's pretty much all the game made me feel by the end.