I can see a Nashville crack backfiring, tbh.
I couldn't. People underestimate a few things- how Republican Nashville suburbs are, the significant pockets of GOP strength within Davidson County, and that Nashville proper isn't even big enough for a full district. Nashville is surrounded by TN-4, TN-6, and TN-7. The sum of the Cook PVI's of those four districts (including TN-5) is R+57, which means it's possible to split Middle Tennessee into four R+14-15 districts (which actually mean 30 point GOP wins, as in 65-35).
What sort of PVI is required to be considered a safe seat?