Thanks- I looked at both. I don't see a solution in either.
Please add details of your issue to this bug report: Lightroom Classic: "An internal error has occurred: ?:0: attempt to index a nil value" | Photoshop Family Customer Commu… Be sure to copy and paste the first ten lines or so Help > System Info. Also, click Me Too and Follow in the upper-right corner -- this will make it a little more likely Adobe will prioritize a fix, and you'll be notified when the bug's status changes.
Meanwhile, carefully read the several comments in the bug report about disabling plugins -- that has helped some people.