How can I fix the bug of deinstalled apps showing in Focus mode?

fendersurfer wrote:

Did that. Though don't disturb can never be deleted.

It may be time for a nuclear option. Reset your settings. Settings>General>Transfer & Reset iPhone>Reset>Reset All Settings. This will remove all personalization. It's not to be undertaken lightly.

Another option is to back up the phone then restore it from your back up. That might or might not work.

Or, you could simply live with it.

Delete the entire focus and recreate it without those apps.

fendersurfer wrote:

I wanted to use reset settings only when nothing else helps.

I agree.

Some say it won't fix the bugs,

It's not intended to fix iOS bugs. It mostly clears out corrupt settings.

but as I use backups for many many years now it might be good to do so one day.

You should be backing up your iPhone every day.

How to back up your iPhone or iPad with iCloud - Apple Support

Also that there is always the possibility that battery drain will happen if you use backups long time. but I am not from R&D.

Backing up your phone doesn't drain the battery as you have the phone plugged in while it's backing up.

Maybe also iOS 18 will fix, some had the experience from 17, or 16 and the big update helps to resolve the issues.

As it is most likely not an iOS issue but an issue with your phone, I wouldn't count on that.

What happens if you delete the apps from the Focus?