Whoops, forgot to mention the name. The company making the sensors is InfiRay. Doogee doesn't even have a product listing for the V20 Pro on their website currently, although you can find one on archive.org that says they're using the Tiny1-C sensor from InfiRay: https://web.archive.org/web/20230601144956/https://doogee.cc...

I searched AliExpress for Android phones with thermal cameras, narrowed it down to three brands (Doogee, Blackview, ulefone), eliminated Blackview because all of their product listings proudly mention that the thermal cameras are by FLIR, and then opened a bunch of tabs to compare specs and search YouTube for review videos that seemed like they weren't paid for. The video I linked above in my comment is from a prominent electronics YouTuber who explicitly states that he bought it on his own and I found another video comparing the FLIR One Pro and S98 Pro that looked promising (https://www.youtube.com/watch?v=QQ7NJPvPsk0), which is why I'm deciding between the two options from Doogee now.