I read a question here about this topic but actually I am not super sure whether I understood it correctly. Unfortunately, because of my low reputation I can't comment there, so I decided to ask here directly.
I think I understood in general the difference between UDP and TCP. Running an VPN on which I transfer files would make me want to use TCP as I want the data to be correct and complete. However, I read this post here, https://security.stackexchange.com/a/27844/191246. From this I got the feeling that with VPN it is a bit like a box in a box. So the inner data transfer is performed with TCP all the time, no matter whether the outer box i.e. VPN is using UDP or TCP.
So that would mean unregarding the setup of the VPN, let it be UDP or TCP, I have the guarantee that my files are transfered correctly. Is this right?
I want to replace my FritzBox VPN by an OpenVPN running on a Raspi and I really want to understand what implications are caused by certain decisions.
Thanks a lot, for your comments.