Similar to this, I tested out a rule that copies invites received into an inbox subfolder folder and marks them as read. See rule settings screenshot below. For those who new to rules, in the new Outlook it is under Settings (gear symbol) > Mail > Rules.

Took me a while to select the folder that I created to house the copies, as the list of available destination folders didn't match what I saw in my left-hand folder list under Inbox, but it was there when I searched for it. So, now I have a copy of all invites received independent of main inbox and trash, if I ever need to go back and check one.
You could make a rule that copies it back into the inbox and marks it as read, so when you accept the original, the read copy is all that's left. But I feel like I wouldn't like seeing double invites in my inbox, and I actually have to scroll less when looking for old invites if they are archived in their own folder.
Thanks to @Daily_MS_User for the above workaround which gave me this idea. This issue is pretty much solved for me now.