Ok so I do not have a perfect answer to fix every problem, but what I do have is a list of things that you can try when having problems with Final Fantasy X/X-2. I usually will leave this as a comment on someones post in the discussion forum when people are having issues, so I figured I could just post this here for those that I am unable to get to.

I made this list a while back, and some might not pertain to your problem but they are always worth a shot.

Try this first
Steam > Library > Games > Final Fantasy X > Right Click > Properties > Local Files > Verify Integrity of Game Files.

If this does not fix the problem then try running steam as admin. (Hover over steam desktop app > Right Click > Run as admin)

You might also try disabling steam overlay. Open the steam app and at the top left click Steam > Settings > In Game > UnCheck Enable the Steam Overlay while in-game

If this doesnt work check your firewall is not blocking anything related to the game. <--Seriously people think this is not the cause so they dont check, but it might very well be your problem!

If you are using an Nvidia graphics card follow this step.
Nvidia Control Panel > Manage 3D Settings > Perferred Graphics Processor > Change to high performance.
If you are not using an Nvidia device then the steps should be similar just replace Nvidia with the name of your device such as AMD

If that does not fix your problem then do this:

2) Go to your files. This PC > Local Disk > Program Files (x86) > Steam > steamapps > common > FINAL FANTASY FFX&FFX-2 HD Remaster > hover your mouse over FFX application > Right Click > Properties > Compatibility > Run Compatibility Troubleshooter

If this does not fix your problem then I have to ask, are you using the UNX mod? If so then I recommend one of two options, either A) Follow the uninstall guide for the UNX, it is very simple, and do away with the UNX. or B) Downgrade to the previous version of UNX. This seems to help alot of people with the UNX crashes. If you do not know what UNX is then you need not worry about it, because you do not have it. UNX is something that you would have had to install yourself.