OP,
I forgot about a new lower cost solution.
I know you said DJI, but Autel now has the lowest costing 640 resolution (640 is the current mainstream drone thermal resolution. Lower than 640 will have issues such as limited range).
The Autel Evo Lite 640T Enterprise Edition @ ~$3300 to $3900.
It does have some interesting features such as AI object detection, a decent flight time, small and portable.
But I would heavily research this drone first. Autel is notorius for not adding all promised features, short life cycles, not so smooth firmware updates. With that said at work we have and Autel Evo 2 Dual (FLIR original version) and she still does her duty well. I have viewed many Autel Thermal images and they are of high quality.
I am with GadgetGuy, if you find a used DJI with thermal (Only look at the Mavic 3T and
Mavic 2 Enterprise Advanced as they have the 640 thermal sensor), go with that. But with shortages of the Mavic 3T, you will most likely not find a low priced deal.
If you buy a used DJI drone, MAKE SURE YOU GET PROOF FROM THE SELLER THAT THEY DID THE UNBIND PROCESS!
Sorry for yelling but there is a current thread on the forum where a member has a drone bound to another account.