The UI buttons in the Player Dressing doesn't respond....
This occurs when you have no internet connection, especially with your account signed in while offline... And it always happens on android.

Edit: I've been wanting to use my custom skins while playing Minecraft Offline. It seems that this really needs lots of fixing. It also still affects th latest version 1.21+.

For some reason, it requires me to be online or to have internet connection to actually change or select skins on the dressing room. I never knew it could also happen in some platforms. But in most cases, it happens on mobile devices since it is where I always play Minecraft.

For my Evaluation: Playing Minecraft while offline limits the use of other crucial features and etc. such as the Dressing Room.

HOW TO REPRODUCE:

STEP 1: Make sure that you're offline, in this case, connect to a network that does not have any internet connection or if best, just don't connect to any network.

STEP 2: Open Minecraft (I recommend playing it on mobile devices) and go the dressing room.

STEP 3: Press any UI buttons such as Create Character or etc.

Expected Result: You are supposed to be able to create or edit skins.
Observed Result: The UI buttons won't work, thus prohibiting you from creating or editing skins.