In version 22.214.171.124 of the Gallery plugin for Ultimate Member, the addon user control was added.
To enable this feature, you must go to the Admin > UM Gallery Pro -> Settings and click on the Addons tab.
Then under User Control, click Enable.
Once enabled, go to the General tab and select the Roles that will be allowed to moderate a user’s albums and photos.
Now, that’s it. Any user with the selected role will have the option to go to a user’s profile view the Add/Manager album button and edit the user’s album, photos and videos.