iPhone Wifi showing connected yet no internet, cannot disconnect

On iPhone 12 mini with current OS, has been happening on the old versions for about 4 months now.

This problem has happened before I updated to the current OS, however, the problem is now worse.

This problem occurs about every hour or so, where on the top right it shows that my phone is connected to full bars of wifi, however the internet fails to load. When swiping into the quick menu to disconnect from Wifi, it refuses to disconnect, and will show that phone is still connected to wifi. When going into settings to check the wifi, it shows no wifi name and clicking on wifi will freeze the settings menu.

The only solution to this that I have found is that when restarting it fixes it for a while, however the issue will happen again after a few hours or so, and has been getting worse in the recent month. I have taken this to the apple store, and the physical wifi component appears to be functional, and the technician did a network reset (mentioning it may do with vpn settings), however, after a day the problem came back. They also recommended that I do a full system reset, however, I don't know whether this will fix the problem, as I don't wish to do that quite yet. I doubt this is an issue with my carrier, as my relatives on the same plan and similar phone do not have this problem.

Is anyone else having this bug, and have any solutions?