1* Unfortunately, I just hide tabs that are not in current group. I cannot replace original ctrl+tab/ctrl+shift+tab shortcut keys, which switches tabs by tab strip (on top) order. When activated tab is "out of range of hidden tabs" My only choice is to switch to group where it is located. Sorry :(
2* I have it in plans. For now it's "compatible" with chrome/vivaldi/opera where containers are not present. I have to "split" some code to make that possible.