Dell G7 7588 Frame Drop Issue

I have a Dell G7 7588 that i bought in December of 2018.  It was working fine until recently, when frames started randomly dropping (to as low as 10-12 fps), even in low-demand games such as DoTA 2.  I regularly do a rudimentary fan clean (remove the back panel and blow air through the fans).  I have also done an undervolt using ThrottleStop, but this doesn't solve the issue.  I literally get better frame rates when the laptop is unplugged, because at least then it's a consistent 30 fps.  It is highly disappointing to have a laptop with these specifications, and see frame drops like this.  Please help.  

P.S. I read on a forum that a recent BIOS update in February of 2020, which reduces the maximum speed of the fans is a cause of this.  Whatever the cause may be, I want my problem solved.  I'm not spending so much money on a gaming laptop, just for it to become a paperweight in around a year.