Question Git o Docker?

[WhiteTiger]

I have to install several applications that I find both with Git and with Docker.
I read all the documentation in Plesk but I can't tell if it's better one or the other, especially thinking about the updates.
These are applications developed by others where at most I will make small local customizations that I will NOT share.
I did not understand if I have to associate each application with a subdomain or if I have a URL like apps / mydomain.tld / app1 or / app2, / app3, ...

Thanks in advance