@ Old Bruce:
Yes, of course that's possible, but unfortunately it's a bit cumbersome because, in contrast to Affinity Designer where you can select all layers with a hotkey, it's unfortunately necessary in Affinity Photo to first go to the "Select" menu to choose "Select All Layers" to accomplish the same.
I wouldn't call that a workflow.
Yes, of course you can define a custom shortcut but to be honest I also prefer to avoid non-standard hotkeys.
@ carl123:
Maybe worth a try. As a workaround for now.
Although I'm of the opinion that this should actually be an out-of-the-box standard functionality.
Hence the feature request.