For Windows, the paid program SuperDisplay will also allow you to use an Android device as a second screen, works wireless or over USB. My Galaxy Tab S7+ is great as a second monitor. https://superdisplay.app/
I also have an S7+, and I've been very happy with the device. How do you feel about it in 2023? I'm tempted to get the S9 Ultra as an upgrade but I'm on the fence right now.
No significant improvements were made in the last 2 gen