Launchbox is definitely the nicest frontend I've tried on the Retroid Pocket 2, but the RP2 really doesn't seem to be up to the task of running it. Just browsing and scrolling down my list of games causes it to drop out of Launchbox. Some systems I can't use because as soon as I try to scroll down the list it just crashes out of Launchbox. I've got about 13 systems in Launchbox with the list of games in each ranging from about 5 or 6 through to just under 100 in a couple of those systems. The longer lists are far worse, but the crashing out can also happen on much shorter lists too.
So yeah, it runs, looks great, and I really like it, but if you are using it on the RP2 then keep your expectations (and your game lists) low.