I had this same issue for the longest time and so irritated after spending almost $7,000 on two 16" Macbook Pros and BOTH having the same trackpad issue. SOLVED FINALLY!
After updating to 10.15.6, I noticed a short screen refresh black screen pop-up to I assume they tried to "help fix the trackpad". I noticed it helps fix. But there are still times that it continues to happens. That was not enough for me.
So I spoke with an Apple representative and she first recommended to put in Safe Boot mode while allowing the device to fall asleep.
Still didn't work so we proceeded by resetting the SMC and NVRAM or PRAM and so far no problems with the trackpad! I also turned off force click and haptic feedback and installed anti-malware software as well.
You can find the explanation on this website.
Note: Resetting these does not affect any of your applications or anything so don't worry!
I hope this message helps resolve your issue. Let me know if yours gets fixed too!
URL:
https://www.makeuseof.com/tag/reset-macs-smc-pram/