I think a good litmus test for if something is a good argument is to see if it is something possible to disprove by proving the inverse.
If you were to take this argument:
It is nearly impossible to get an honest current thought from a Chinese citizen about that... and therefore Chinese must not served/satisfied by their government.
So the inverse of that would be "it is possible to get an honest current thought from a Chinese citizen." So since that is not something I can prove or disprove your claim tells basically nothing as well. This is because even an actual Chinese person telling you their honest thought cannot prove to you, by your standards, to have given you their honest opinion because you make hand wavy arguments that their true opinions are being suppressed already.
You've already disqualified any potential rebuttal because saying "that tells you nothing" can be literally applied to any data or stats thrown at you... because your whole argument is that the data/stats/opinions of Chinese people cannot be trusted.
> Some wealthy Chinese have a designated family member move to hedge their wealth preservation bets while galavanting around in a western country. I don't think trends in that metric reveal anything except how many are willing to play that game.
You can literally apply this as a counter argument to anything. I could claim that Americans' satisfaction with their lives is just a select few that you happened to talk to that are rich and galavanting around. The only way to counter this would be to catalogue every single person and of course also audit that every person was accounted for because any survey covering people can be discredited by saying that it didn't count everybody or that answers were given under duress.
The reality is that not even 20 years ago most Chinese who left did not have plans of returning, but given improving conditions the rate of repatriation is increasing. After the revolution people tried to escape, but that's not the case anymore. Rather than automatically discrediting any Chinese or stats that go against your pre-determined narrative, which is not something people can argue against, present evidence that can actually be proved/disproved.