Occasionally, a problem where NVDA shortcut commands such as read title bar, open menus, etc. stop working has been discussed here.  I may have found out what is actually going on and it may either eliminate or almost fully eliminate the need to unload, then run NVDA again.
It appears to me that a key is getting stuck.  When this happens, try pressing the left shift key, then the right shift key quickly perhaps five or six times each.  Then see if the commands work again.
Caution: It used to be and probably still is the default that if you press either shift something like five times, it will turn on something.  I don’t recall if it is some sort of sounds Windows will make when certain keys are pressed or sticky keys.  At any rate, if you haven’t turned off this behavior, don’t press the shift five times.  Try three or four.
I’ve just been trying this recently.  I don’t have this happen enough to see if the same key, for example, one of the shift keys, or another key, such as either control, either alt, or the NVDA key, gets stuck in new occurrences or if the same key gets stuck and no others.
Experimentation by people will answer that question.
If it turns out to be keys getting stuck, that may lead to a solution.
Gene