Nashville isn't super cheap. I live in Baltimore - the listed minimum living wage is around 25k, and I spend around 18k (for example, listed expense of housing is around 9k, which is reasonable, but I own a house share with my S/O, so my yearly housing is like...5k including putting money aside for maintenance.)

Grand Rapids living wage is 21k per year. Lansing is just under 21k. Birmingham, AL is also 21k per year. Missoula, MT is around 20k. Cleveland is 20k. Pittsburgh is 20k. York, PA is 19k. Durham/Chapel Hill is 22k. These are all nice places, imo, although not everyone would agree. But, a lot of people are happy living in smaller cities. It's not like there's no culture. I live in Baltimore and the BSO is a top tier orchestra. I grew up in Pittsburgh and Carnegie museums are amazing and there are lots of great, inexpensive activities for kids.

It seems hard to find a spot under 18k anywhere, but 20-22k in pretty much anywhere outside the top 20 biggest cities seems easy to find (although there are some cheap ones in the top 20, like Baltimore, which is the 10th biggest and St. Louis, which seem like value cities for culture/ameneties vs. cost)