Custom calendar's dont seem to delete

[ArticSkoll]

am trying to figure out how to delete custom added calendars that show in the list on the samsung calendar app but the only thing i seem to be able to do if i tap/hold on it is change the color coded labels of the given calendars themselves, i cant delete/unpair them in any way. 

not on my old note 10+ nor my brand new S25 ultra. 

[HennyHendo]

I'm having the same issue. I want to completely remove the CompTIA exam calendar but the only option is to change the color. It is not attached to Google at all, this is My Phone's calendar. I've looked into the Accounts and Backups and there is no option for calendars.