@Kabam Jax I saw this response that you posted the other day, but I'm still having this issue and my game is NOT sideloaded, as you claim the issue is coming from.

I have my alt account on a second copy of the MCOC app downloaded DIRECTLY from the Google Play store in my Samsung phones Secure Folder. Secure Folder, if you didn't know, is a feature of Samsung phones that allow you to install a 2nd copy of an app within it, again, only from the Google Play store.
I'm still unable to play that account, and it would be appreciated if you, or someone else could find an actual solution for it. I'm sure the sideloading may be the case for some other players, but not for me
As others have mentioned, the infinite loading bug seems to happen when interacting with certain newer champs. Ones I've had the issue with so far (that I can remember) are Toad, Wong, and Spidey Supreme. These champions can't be fought, or even interacted with: I pulled Wong as a 6 star, and when I try to go into his champion info in my roster, I'm also presented with the endless loading bug.