I do both when it comes to static IP addresses. Assign the static IP address to the desired device and then reserve that static IP address on the router for that device. Plus I use a static IP address outside of the allowed DHCP IP address range.
Reason being that if the device in question (i.e., 192.168.1.13) if offline another device could be assigned 192.168.1.13 by the router.
Distinction being that the router knows not to assign/use DHCP IP address 192.168.1.13 for any other device except the device (by MAC) for which 192.168.1.13 is reserved for.
So no disagreement with
@bill001g. (Thank you.)
But reading your response I have a question: "Are you hosting Minecraft on your pc or on another computer/server?"
I.e., your PC and the server being one and the same physical device or are you using two computers?
See the following link with regards to your hot box and port forwarding:
https://portforward.com/hot/hotbox/v2/
There is also a Version 1 available at the top of the link: "Hot Hot Box".
And doublecheck the port forwarding requirements for the games you wish to play.
E.g. Minecraft:
There are quite a number of "how to" links to be found. Go to the source:
https://minecraft.gamepedia.com/Tutorials/Setting_up_a_server