Well, this convinced me not to use UGOS completely: https://www.youtube.com/watch?v=ShZHCS2ynp4
There are a lots of pinging to China and while most is for DNS lookup, there needs to be more technical knowledge involved to block certain connections from happening.
As for using TrueNAS on a UGreen NAS, it seems safe: https://www.youtube.com/watch?v=EPmjdrYWOpQ
I don’t know about kernel security that @anon63378639 mentioned though, so I’m not sure what I’ll do.
This topic’s question has been answered. Thanks everyone for chiming in!
I will continue the discussion here: Thinking of switching from QNAP to Synology or Asustor