It was originally running Android 9.0 but recently updated to Android 10. Didn't realise that it is missing anything until I got an A71 mobile and found the screen record option.
Is this an upgrade to 10 glitch or simply Samsung disabling the feature on tablets?
I did but no luck. But I think the reason is the user interface version. My A71 mobile is running One UI 2.5 while the tablet is only One UI 2.1. I guess there more to it than just Android version.
Then you'll need to scroll to the right on the drop down icon menu pictured. I have a Tab A 2018 10.5" on Android 10 and the icon for this function is in there.
UI 2.1 (my tablet is older but has the same UI as yours). if you do scroll to the right/drag the icons to the left after pulling down all the icons, are you seeing the additional icons (at all)? I didn't realise that there were a few more there until I came across them this way. The other way to see the additional icons to choose from is to tap the tiny empty circle right beside the filled in circle at the bottom of the pulled down icons.