First of all, RDP.
In thinking about your drop issue, I have a couple of ideas that might be the cause. However, I would need to create and ask a series of yes/no/short answer about your current configuration in order to understand your network, its settings, (e.g. IPv4 v IPv6, which is turned on or off, etc.) what may be or may not be the cause.
Seems like you have done most on-hand troubleshooting already however, I would need to take a look at your methodology to determine whether there are different, perhaps better, approaches you haven’t considered.
I’m not going to guarantee I can fix it, but I will put in the effort to research, probe, test, troubleshoot, etc. to help give you the best chance to resolving this issue.
Best,