You can try disabling the Steam Overlay, this can cause issues but its not that common, in Steam > Menu > Settings > In-Game > uncheck the Use Steam Overlay.
Try that and see if anything changes.

Next I would disable the Nvidia Geforce Overlay, this often causes stutter, find it in the Nvidia Experience app, top right cog and its in the settings some place just have a look through the options.
Try it with it disabled and see if it stops stuttering.

Next you can try Windows Power settings, often Gaming Laptops default to the "Balanced" power plan, this often causes stutters as the GPU will be affected first, in Windows > Start > Settings > System > Power and Battery > Power Mode > Select "Best Performance" and test, if its on it, try "Balanced" to rule out issue.
If nothing changes, check Nvidia Control Panel app, go to 3D tab, select FFXIV from "Programs list", make sure its sill got "High performance" under .2, in the list down below with lots of options, scroll through the options and check "Power Management mode", it should say "Optimal Power", try "Prefer Maximum Performance" and test in-game.
If nothing changes, try that last option on "Consistent" then test, and "Diver" and test.

Check in this same list down the page "V-Sync" is set to On or Use 3D app setting, if its On, put it on 3D app, if its 3D app, put it to "On" and test.
You may have G-Sync options as well some where in the app, if so check what its set at.

I don't think you'll find its the card, but you could test in other games, does it stutter in only FFXIV or multiple games, or all?