Basically is like to know if it's possible to have linux as a base and only have 1 main program to run on it. If the system reboots it loads that one thing. There is nothing else to load.
Would i simply have to set that linux run that program on startup but then I'd have to load an entire desktop system under it right?
You can change the startup mode from graphical to multi-user
That then does not start the X server at all, you just have a command line or SSH interface.
And, create a script file
/etc/rc.d/rc.local
then put any commands you want to run on startup in that (at least, on Fedora 31, which is what I'm presently running on some Pi boards).
You can use that to start your dedicated program, with no xwindows overhead.
To disable xwindows at start on that distro, you run this from a terminal:
systemctl set-default multi-user.target
At the next start you will just get a text login prompt on each terminal.
Other distros may well need different commands.
I'm using a Pi board configured like that for dedicated Quake II deathmatch server.. The game itself and serverconfigmod addons were compiled on the same board, with gcc etc. installed.
Fedora for the Pi, if you want to try it: