I'm not sure if you looked in the notification pull down area or not but that's where mine is an I have a Note 20 pull it down as far as you can go an search thru each widget I believe they call it tell you find one that looks like a camcorder that looks like it has a triangle in each corner holding the camcorder in place I guess. Hope you can find it an that my guide was some what useful lol.
Unlock your first screen scroll down from top and open the Quick settings like wifi click on live capture and press record when you have what you were looking to keep tap the stop and then you can review or save/ send / copy or whatever
try to pull down the quick menu guide again fully look for the 3 dotted line next to the settings button. click it an hit edit buttons you should be able to find it in there an have it in your menu of widgets