I moved my family successfully to Signal a few years ago, and so far I’ve only very rarely encountered issues with video calls

Shouldn’t be impossible. There are addons for Zotero (reference manager) to check CrossRef for citation count and one of the post-publishing review platforms for comments on the paper.

My Pixel is taking short video snippets from which you can then choose the best frame, and so far no other app than GP is able to handle those (as far as I know at least).
Can Immich work with those?

Raccoon, second best is Eternity