XII and XV just straight up have Denuvo in them
VII and VIII still have the weird Square Enix account DRM in them too
edit: might as well finish off the mainline FF Steam sin list
FF I & II do not exist on Steam (not counted in total below)
FF III-VI are ports of the mobile versions (the mobile port of III is a port of the DS version though and not those shitty artstyle mobile ports, that one's good I think)
VII and VIII have the weird SE account DRM
IX: fine, except the music bug which plagues all of the new ports
X/X-2: see this thread
XI: fine, just downloads the client through Steam, you can even mix and match Steam and non-Steam base game/xpacs unlike XIV, key that Steam gives you is no different from anywhere else
XII: Denuvo
XIII trilogy: awful ports
XIV: fine, you have to buy xpacs on Steam if you bought the base game there, I don't really consider it a big issue, ESO does the same
XV: Denuvo
That's 4 (III, IX, XI, XIV)* out 16 decent ports, good job SE
*I'm not sure I'd count XI or XIV as ports, they were developed for PC equally alongside console versions, so drop it to 2 out of 14 if you want