Verizon 5G Internet Support is not at a high-enough pay grade to assess this problem... So I'm turning to y'all.
I'm trying to save $$$ and increase speed, using Verizon 5G Home Internet to replace XFinity, even though they gave me a faster modem a few weeks ago. I run both of the modems in Bridge/Passthrough mode.
A friend of mine is nice enough to offer some offsite backup space, and I use rsync over ssh to get there. He's 1500 miles away. He uses a non-standard ssh port (keeps the doorknob twisters away). This sort of thing has been working without difficulty over Xfinity (my end) for years. He also changed his connection almost a month ago now, to Qwest, I believe.
I try the same thing over Verizon  and ssh always times out, no response. We are also NTP peers, and that doesn't work well over Verizon either. ICMP traceroutes and pings succeed. UDP traceroutes do not get any further than 18.104.22.168 (last hop before destination) . Not every traceroute offers TCP, but MacOS does, and nothing responds to any of that, even at the usual ssh port. UDP traceroutes to either port behave like an ordinary one, which it is.
Since I can get there via xfinity, I can traceroute, ping, but not ssh back through Verizon.
I also set up an incoming (xfinity) port from the same non-standard ssh port forwarding to regular ssh on a different system on my LAN, and when I ssh -p <port> that from Verizon (even cellphone data), I get that other system, and that works fine. The 207... router is not in that path.
I can also ping the Verizon connection from Xfinity (and vice versa).
 This same difficulty occurs in Verizon's Looking Glass, from several different places, and other Looking Glasses (e.g. Cogent, Equinix). It also occurs on my Verizon phone data connection (not WiFi). If he were serving more stuff out of his home, this would be a bigger problem.