>>314866641well, they're kinda different sort of RPG games.
X is a more traditional main-series title, with a bit more linear world design and truly turn-based combat. It was also the first one to have voice-acting, which kinda caused controversy back in the day. A quite enjoyable story all around.
Type-0 is much more action-y game, and a spinoff title to the series. It was once meant to be one of the FF XIII "series" titles, but in the end those plans were demolished and it became its own title, just like Versus became FF15.
I'd probably give X & X-2 HD a go at first. They're quite comfy and simple JRPGs.
You can get Type-0 for PC as well.