Quotes for other stuff like hardwood floor installation and finishing—a job I'd personally consider harder and requiring greater skill than installing a mini-split in a totally uncomplicated setting—was extremely cheap by comparison.
The electrical work I need done is because the previous owner (my grandfather-in-law) built the house and did absolutely NOTHING to code, and inspection found none of this. There are splices in the walls, there is yellow romex being used as power lines to sub panels across the lawn, strung from tree to tree to keep it off the ground. The electrical panel is installed 5-inches from the washing machine... where there is water, and lots of it. There are 4 sub panels strewn throughout the house - it is 1300 square feet. There are random nutted romex wires just poking out of holes in the walls. Basically we need the entire house to be rewired.
Same with plumbing, there isn't a single valve in this house. Everything is plumbed directly from the cold or hot lines. So when the shower sprung a leak, we had to turn the mains water off, rip out the shower to fix it, then re-install it. And that is all over the house, as well.
Don't buy a house built by a family member, even if that family member is a GC that builds houses for a living, because they aren't getting paid to build their own house, and will 1000% cut every corner known to man.
Its very much like an experienced coder going into established codebases and being able to more quickly make changes and improvements. No codebase is perfect and they all seem to have their own uniqueness just like no house is perfect and all have their own quirks. How good or bad it is can be determined by the experience and foresight of the person doing the work but there will still always be uniqueness and quirks.
Once I finally internalized it, I really appreciated the history of my home and the things people did to solve problems as time went on just like a mature codebase. I would argue as long as the property is generally good, its just a fact of life to have to deal with the rest.
That's not to say a good inspector will find every fault either. They don't tear walls open, and they don't have x-ray vision. They only inspect what they can see.