I hired someone to finish my basement, and was kinda astonished how quickly it came together. I'm not saying anyone could do it, but it didn't look super difficult.
I would never do electrical or plumbing myself.
Years later I had a crew build out my back yard, and that was way WAY more work than finishing a basement. In particular, it's a TON of work to date a dirt lot, level it, wait for it to settle, level it again, etc. The preparation of the building site is royal pain in the ass.
They removed the reserve requirements because Covid. They're zero now.
https://www.federalreserve.gov/supervisory-regulatory-action-response-covid-19.htm