ScreenRecorder for windows will give you a floating palette. You select a region you want to capture. You press record to start recording. You press stop to stop recording. The recording is saved on your desktop.
I wanted to make a fully self-enclosed, screen video recorder, that wasn't adware or worse. One that I could trust. I couldn't find one, and because Microsoft's screen video recording tools are woeful, I decided to do the decent thing and write my own.

Download ScreenRecorder for Windows 10 / Windows 11.
If you have any suggestions, please get in touch via email. Many thanks.
Tom.
tom@tsites.co.uk