I do not want to update any apps automatically. I want this to happen at home when I am not charged for data volume. Are these settings correct for my wish? If not, which settings do I have to change also? I do not care about possible security issues that may arise. I can update from home manually once in a while.
On Oreo 8.0 and should be similar on Nougat
Apps: Play Store Settings → Do not auto-update apps or Auto update over WiFi.
There is a third option Auto update at any time - Data charges may apply. By selecting this and selecting Auto -update for an app you ( from 3 dots menu) you can select apps that you wish to update over data connection
These settings do not apply to system apps like Play Store, instant apps and they get updated even on data
OS updates: in Developer options disable automatic system updates and manually update, since these are typically big size files and accidentally downloading costs data
In your case HTC seems to have a different UI ; disable the second option to prevent accidental download as explained. System updates aren't that frequent anyway