Even Parrot sell spare parts, although for things like camera, especially on the Thermal, it might be looking for the holy grail.
Checkout the Classifieds in the various drone forums, I know there was someone on here selling spares.
Apart from that, your only other option is to replace your Anafi with a new/refurb unit, and break yours for spares and sell them off, you'd be surprised how much you can get breaking an Anafi, especially the Thermal.
I think you will struggle at the current time to pick up spares for the Thermal model. Hass been a few crashed, but I guess given the significant cost difference, the users may get better assistance with Parrot support, also most will still be under warranty.