Hi! I’ve also experienced the same situation that you had with your cursor not clicking and basically malfunctioning. It happened twice and the second time, resetting the PRAM, SMC and even safe boot (safe mode) eventually did not work for me. I really thought my trackpad or my laptop was gone (Macbook Pro mid 2014). Even when I used external usb mouse, the cursor was still not clicking. It can move but it also randomly moved on its own, you can do gestures and right click but that’s it. So whenever I try to reset the PRAM, SMC, and login in safe boot, I have 5-15 minutes normal cursor time. I then manage to follow the advice of someone who commented here that states turning on the “ignore trackpad when external / Bluetooth mouse is used” will also help. So tried using my external usb mouse and this actually worked for me, I used my laptop for 7 hours without the cursor malfunctioning. But of course I can’t use any gestures since the trackpad was still not working which was annoying. Now, apple released an update Big Sur 11.2.2 I think what its called. It had bug fixes for external ports not working something like that. After updating my laptop (Macbook Pro mid 2014), I turned off the “ignore trackpad when external / Bluetooth mouse is used” and my trackpad works normally now? I’ve used my laptop for about 3 hours without any cursor seizures. NOTE: My external usb mouse was also plugged in but I also tried using it with the trackpad alone and it was still going smoothly. So I think the update fixed the bug. I’ll update you guys when I fully use my laptop for like 10 hours and see what happens if it the update really fixed the bug. Hope this helps! : D