External Display not recognized after screen was locked

I am using Ubuntu 20.04.1. I am using a Laptop with Nvidia GPU and the newest proprietary drivers (Razer Studio with Quaddro RTX 5000). At home I use the laptop connected to an external display with setting the display mode to "external only". This works fine until I lock the screen. The external display would go black, but when I try to unlock the notebook again, no screen is turning on again.

I have to unconnect and reconnect the screen multiple times then it goes maybe on again and works (I guess a combination of OS behavior and Display energy management), or the second option is to unplug the display and use a shortcut on the notebook to switch display modes until the internal display comes on again.

I deactivated all power saving features, basically to not turn of anything anytime, but it did not solve the issue. As soon as I lock the OS, the screen goes off and I got the issue again.

I see two possible solutions:

• Chang xrandr or some setting, so the configuration of the screen is never updated automatically but just kept as is, until I manually change it. (but I couldn't figure out how todo that)
• Somehow tell Linux to not turn off the displays when I lock the screen, since I expect this to be an issue with the display going into some power saving mode and then it is just not recognized anymore.