There's no right way, really. You can turn almost anything into a server.
If you have old hardware laying around I suggest you start with that. When you're comfortable with setting everything up and using it on your day to day, then it's time to invest into hardware.
I feel like we were so close to having Jarvis like assistants. Then every company decided to replace the existing tools with their alpha state AI, and suddenly we're back to square -1.
There's no right way, really. You can turn almost anything into a server.
If you have old hardware laying around I suggest you start with that. When you're comfortable with setting everything up and using it on your day to day, then it's time to invest into hardware.