It depends on your threat model. Using tor via a know vpn endpoint does make you stand out and can be used to profile your traffic. One of the main points of tor is that all users look exactly the same.
If you have e.g. one user out of a 100 using a vpn endpoint instead of some residential ip address that user immediately becomes a much more interesting target. There is information floating around in the web that state actors have control over several entry and exit nodes.
You got most things right about UDP and TCP. They both work in the transport layer of the OSI model. They are also completely different protocols, related yes but independent.
UDP is "simpler" as it basically throws data packages in to the network and hope they reach their destination. TCP on the other hand has checks in place that verifies that a data package has actually reached its destination.
This is or was part of their anti-spam/flooding protection.
That's the official explanation. A phone number is a nice way to attach a real world identity to the data (which of course is sold to advertisers/data brokers etc).
Wayland has at least one deal breaker for me. It doesn't remember where my windows were at logout when saving the session. I have six virtual desktops and have specific windows in certain desktops. Putting everything back where they belong after each login, no thank you. Until they add that I'll stick to X11.
X11 can be easily forwarded over ssh. You do need to have at least the application you want to forward installed on RPI, possibly X11 as well. You also need a X11 server on the other side.
Even youtube doesn't pay the creators that much. Lois Rossman in a recent video showed some of his video in YT that had over 200k views and generated ~100 USD of income.
laughs in btrfs and xfs