A tension filled grip, especially from having the shaft too much in your palms, will kill your entire swing. It stops your wrists from hinging naturally and then works its way up your arms and into your shoulders and locks up your entire swing.
You can’t fix your swing flaws until you establish a repeatable golf swing that goes down the line every time so your errors are consistent and can thus be fixed
A waggle is a great preparatory motion to get your wrists, elbows and fingers loose and ready to swing