Every item created on a Master Page should be able to be made local on the child page. InDesign handles this by CNTRL+SHIFT+CLICK and I use it in virtually every project.
The lack of this feature makes Master Pages far less useful.
Consider it requested!
PS: I have purchased everything Serif offers in the Affinity line, really pulling for you guys! Publisher is the last step I need to quit the evil Adobe ecosystem. Thank you for all your efforts!