Actions and Stuff add on by oreville studios does not allow for customization of the resolution when on Realms. This is a consistent problem that many have voiced. It’s clearly a problem with realms not the addon. We are unable to edit the texture pack unless we use through Global Resources which doesn’t apply to other players.
Duplicate bug report: REALMS-10307
https://report.bugs.mojang.com/servicedesk/customer/portal/9/REALMS-10307