Thanks, pooya87! I now understand the correct validation method of Private Addresses. That info is really useful but also made me aware I really only need a pattern check, as kano explained.

NotATether was nice, too. I never found that regex in Binance API docs but I did not read those docs thoroughly when I was messing with them. All the discussion about the pattern regex was interesting (I know you guys are making history here) and I was able to add the mainnet uppercase BC1 regex to my collection as that case was not covered yet.  Cheers!