As of 2025 such a feature is still needed imho. Could maybe be implemented as a plugin. Basically a way to find and replace over all notes. Ideally with an optional interactive interface to confirm each occurence.
Plugin: Search and Replace - #20 by netweaver1970 is worth mentioning here.
UPDATE Combining the regular search over all notes with the plugin above actually works very well and let me update many notes in a short amount of time. Problem solved for me.