Mine are the pretty much the same as above, I have two FVs in the garage suitable wrapped up but with a Brew Belt around the base of each, individually controlled, one with a home built STC and one using a Inkbird, both holding close to 20C in an ambient of between 7 - 11 at the moment.
I don't have the space for a fridge so I use the belts for heat and the ambient for cooling.
One thing I may try through is after seeing my local HBS this weekend he had one taped on but sort of spiralling around the FV not just a single band, may help to quell my paranoia of hot spots etc.
But the gist is they work but controlling them is best.