I agree with you that the risk of a 2 hr connection is too high for one who must make the flight or risk a very expensive (or life effecting) summary judgement against them.

To keep the record straight though, the process is not as bad as it sounds.
. The "quarantine" is a walk through with no delay at all. Like other airports, they scan body temp and maybe look for obvious signs of illness.
. The customs (w/o checked bags or T2-T2 transfer) is not the full customs. If the damn machines are working there is little delay.
. Then a standard security check.

If you elect to overnight in PVG, I agree strongly with moondog about going into the ciry instead of staying near the hotel. I stayed near the airport on a 12 hour layover and there was nothing to do.

I still think you should try a few more times to argue with the TA to see how they can help. They probably are contractually correct, but they should have known better than to sell the 2 hour connection on separate airlines.