Semi related article on how to reheat frozen foods without plastic.

Tldr you just pop them out into a glass container and follow instructions as normal. Put a towel over the top if it needs to be covered.

https://ceh.org/yourhealth/easy-tip-making-frozen-meal-healthier/

My understanding is that polypropylene is the most stable plastic (with hdpe coming in at a close second) unless subjected to uv radiation. Of course, it depends on the co-polymer which is almost impossible to find on a product.

Hdpe is not supposed to have an issue with UV radiation however.

I wonder if the radiation that is emitted from a microwave has similar effects as UV radiation.

Our generation’s s lead paint