How can I get Edge to restore all the tabs I had open last session?

I envy a person whose life has so few problems to give them perspective that a browser’s behaviour can make them so angry.

Not if you always minimise the main window to find the others. I always make that the last window I close.

Yours isn't certainly problematic either, since you are so worried about "my" problems, and the way I react to them ;-)

That's a workaround, not a solution. And that would mean assuming that Edge works so badly that we have to take extra precautions, that shouldn't be necessary.

They shouldn't be you're right about that but until Microsoft fixes the problems with Edge we'll simply have to persevere. The main problems are to get rid of stupid things like Co-Pilot and Personal Vault.