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

Because the simple way is to minimise the one with all your tabs then close the ones you didn't open and finally the one with the tabs you want to keep that should prevent that. The one time this won't work is if the internet itself goes down leaving you high and dry if as I said Edge obeyed its own rules we wouldn't be so angry.

I don't do them individually they're all in Collection/ I used to group them but for some reason Edge won't let you put the in Collections as a group.

If you go into the history by opeing it in another tab you can tick all the recent tabs (tick 1st tab and hold shift when you click the last) then you can right click and open all at once.

There used to be now you have to put your most used tabs in collections and even then if you've saved them as a group it won't allow you to select a named group so you end up having to put them in a group again. Sometime later you come back and have to use collections to reopen them, nut at least its a way of getting those tabs back.

Hi there is no "When Microsoft Edge starts" in my Edge settings