I would argue: stop worrying about it. We're what, several decades into this modern software engineering thing and even stuff like DRY, let alone SOLID or what

I would argue: stop worrying about it. We're what, several decades into this modern software engineering thing and even stuff like DRY, let alone SOLID or whatever, still isn't an universal thing. Do whatever works for you, talk to other people, see what they do day to day, watch other people whose products you've used or whose architecture/code you've read and liked do, and don't fret too much.