I prefer subdomains, personally. A lot of services expect to run on the root of the web server, so although you can sometimes configure them to use a path, it's kind of a pain.
Also, migrating services from one server to another will be a lot easier with subdomains since all you have to do is change the A and AAAA records. I use ZeroTier for a lot of my services, and that's really nice since, even if I move a container to another machine, the container's ZeroTier IP address will stay the same, so I don't even need to update DNS. With paths, migration would involve a lot more work.