I, too, have registered just for this topic. It's extremely frustrating to go from Photoshop, Illustrator, InDesign, Gmail, Microsoft Word, Excel, and other applications which follow a similar pattern for ctrl+enter to Affinity, where ctrl+enter irreversibly destroys text.
A possible solution is to add an option ("Exit Text Tool" / "Confirm Text") to the Keyboard Shortcuts panel, or an option in settings to toggle between the two default behaviors (Convert to Curves vs. End Text Editing).
My workflow in Affinity Photo (and Adobe Photoshop) is almost exclusively text-based, and my ability to move back and forth is greatly hampered by the lack of a valid ctrl+enter keyboard shortcut target.