I definitely relate to the bikeshedding thing. I like what someone from Nintendo once said.
"You're making a game. The engine is what's leftover when you're done."
I like to think that way as well.
Sure, I have a laundry list of things to do, but it all starts with a gameplay idea that I want to explore. I force myself to justify all development efforts by way of serving the gameplay ideas.
That way, you're making a game first and foremost and the "engine" is the tool you make to make the game.
E.g. this time around, between a new job and a pandemic, I don't have the headspace to think about my little experimental Roguelike I've been developing over the past year (which BTW. mostly took the form it has from me bikeshedding the ECS pattern).
So when the other day I thought it's time to test out the few things I wanted to test about VR, I eventually decided to screw writing my own code, and now I'm just poking around UE4 and doing everything in blueprints.