Besides the fact, that update-notification does not work at all in nextcloud¹, that’s not the point.
Yes, I could have avoided the problem if I had updated nextcloud prior to the system-update, but the problem is, that nextcloud can get you quite easily into a situation, where there is practically no way to rescue your data.
Reminds me of “You are holding it wrong!”
¹ I never got one, ever. Others also:
No Email notification about new updates
Test mail works <> Mail notifications don't work