Basement house hack viable in TN?

[Michael Douglas Christensen]

Hey BP. I recently moved to Nashville for work and purchased a home with an unfinished basement. The initial plan was to finish the basement and rent it out as a sort of house hack while we live on the main floor. However, my wife has concerns after watching some YouTube videos that basement apartments in TN may not be viable. She mentioned that because the house was built in 1979 the foundation is prone to leaking water and it would be very difficult to prevent this from happening and subsequently destroying the finished basement. She also mentioned that if we install floors in the basement (currently just concrete) it will mess up the leveling with the stairs which will be against code. I don't know much about this but this seems odd to me and I would assume that there are many investors in Nashville that have basement apartment rentals. Can anyone speak to this and help me understand if I should be overly worried about this before pursuing finishing off the basement? I am very much a novice when it comes to DIY fixer upper stuff but want to learn more as I attempt to fix up the basement (and hire out some more complicated stuff).