The main thing I worry about if Loki is able to rejoin the timeline, it basically means everything Thanos did meant nothing, which could lead us down another rabbit hole where someone like Natasha is back or Tony (I know it won't happen bc RDJ is done with the character, but it opens the door, which is my issue). I have no doubt we'll see Iron Man within the next few years in some movie, possibly even in Multiverse of Madness, but i'm fairly certain we're going to see other actors in the role, similar to how we're seeing so many different versions of Loki.