I really don't understand why this particular instance still has to be started from within a particular area, and it also means that you can't queue for it and multiple other duties at the same time like with most instances. You don't even need to be in that particular area once the instance is ready; you only have to go there in order to start the queue process, which is really perplexing to me.

There aren't strict party composition requirements, but I don't see why that should stop anything from a coding perspective since the Duty Finder already lets you sign up for multiple duties that have separate role requirements or even total amounts of players at the same time.

If the reason is because you can't currently join an active Delebrum Reginae instance, then... well, why exactly has that instance not been changed to allow for joining in-progress sessions either? It's honestly really annoying when multiple people leave the instance almost right away and then everyone else either needs to also leave or continue the instance with less players for support.