Dedicated Server?

You don't need a dedicated port, if you don't have a domain, it looks stupid anyway so no point having one, if you have a domain, use SRV records, and ignore the port when you type it in, I can help with the above if needed.

but the question really just comes to...
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You're all wrong really...

Dedicated server means that you can run multiple servers on the same 'server' if that makes sense.

You get one ip dedated to that machine
for example 122.188.12.10 (random ip)
You can set your own ports in the config (depends on what software your server run on, mine run on Multicraft theres also mcmyadmin or something)
so you can for example have 3 servers running on the same machine
122.188.12.10(:25565)
122.188.12.10:25566
122.188.12.10:25567
all running seprately.

If you need any more info you can always PM me. or contact your serverhosts

You just get your own IP instead of having people put something like :25569 at the end.

its mainly for a hub server like mineplex or hivemc if its not going to be a hub you dont need it.

That means that you don't have to use the port when you put the server in your server list.
Also if you were to buy a hostname such at mc.pvp.com, it would not have a port but non dedicated ip means it would look like, mc.pvp.com:28201 (Example Port)