It would be great if the friend campaign could have the option of being filtered into difficulty rating rather than just campaign and disk level. I get sick of having to scroll through the hundreds (feels like it) of hard campaigns that I have no chance of doing yet to find the few easy and medium difficulty campaigns that I can do.
I find I barely do the friend campaigns because I can’t be bothered for the constant scrolling I have to do 
While not the solution you are after maybe, you can go to a character pair’s campaign through their own Friendship menu where you see the Wall and Disk option, there you should be able to find the pair’s Friend Campaign as well.
I preferred the old map option as then I could more so see the characters rather than having to scroll, so yeah now I mainly go through the Friendship menu Campaign option rather than the scroll list.
You can estimate the campaign difficult mainly by when the main Friendship character were released, so this list should help with that:
Even if not exactly what you are after I hope this helps :-).
I usually just 
the ones I want to do so I don’t lose track
Yeah I usually resort to doing that but with 126 unlocked characters (and counting), most with 2 matched friends even that way can get a bit tedious trying to find a level I actually stand a chance of completing. I will have a look at the character list though and see if I can use that to help. Thank you 
There seems to be so many at such a high difficulty it seems impossible that I’ll ever be strong enough to do them and that’s with my team level already being 104
I’m referring to finding new campaigns. Once I find one I can do, I do favourite it to help with next time and it usually moves to the top of the list with the campaign filter on anyway. But finding a new one is such a chore! 