ShareX is a free and open source program that lets you capture or record any area of your screen and share it with a single press of a key. It also allows uploading images, text or other types of files to many supported destinations you can choose from.
The typical way would be to setup shortcut and use that like this (probably you will need to disable windows shortcut or use Ctrl + Print Screen etc.)
Another way would be to use "Capture Region Transparent" it doesn't freeze the screen and let's that pop up to hide away
And one more way to add ~0.5sec capture delay to give enough time for pop up to hide. But that would make capturing quick changing scenes impossible so I don't recommend it
In Every capture I have my pop-up task bar....
Could disable that... I know in old version I didn't see that...
Question in the picture