I thought this was a very well done & thorough article about thermal optics.
Always wanted one, but the different models and time required to research them were too much for me.
https://www.shootingillustrated.com/articles/2020/8/10/how-thermal-optics-work/
For some some comparisons of actual models, here's another article I found helpful:
https://www.berettatrident.com/rifle-scope/thermal/
