I am likewise having the exact same problem as the OP, and NextScript’s advice in https://www.nextscripts.com/support-faq/#a24 is not helping at all.
I have a SNAP Pro premium API subscription. I have three accounts set up for Facebook: one for my timeline, one for my page, and one for my group.
For years, my setup in SNAP Pro has worked fine with all three accounts for Facebook. My password and login are correct. I always update the session ID, etc. whenever it becomes necessary.
Then, towards the end of September, or perhaps early this current month, for the first time, I too began to receive multiple “Suspicious Activity” warnings. I was force logged out multiple times, forced to upload my personal ID to Facebook multiple times, and repeatedly forced to change my password. It was really getting ridiculous.
Then, on October 6, 2019, I was locked out of my account completely. Between then and now, I have uploaded my ID at least half a dozen times. Upon doing so, I always get the “promising” email from Facebook that they will contact me after they have examined my ID. They never do contact me. Thus, I have been cut off from my Facebook friends for 15 days now, and I have no idea when Facebook will let me back in, if ever. It is very discouraging, because I depend heavily on Facebook to drive people to my website.