In current space year then most games are just simple ports without much in the way of divergence (try it on the N64 or even into the gamecube era and different matter entirely as they were often essentially different games).
To that end I could expect, or would at least not be surprised in the slightest, to see you strip off whatever wrapper the switch puts on and be left with basically a PC game compatible (and any other console if you put their wrapper on) save for almost any random game.
Other times you might encounter say a different text setup used, which could in turn shuffle some data around a tiny bit from otherwise fixed locations or formats. A bit tedious to figure out but doable enough if you really really want to. This is also basically the same problem that cross region save conversion encounters -- American game does not support 16 bit Japanese text and also because of that data that followed the 8 characters of 16 bit custom character name is now not in the same place as it was before which rather troubles things expecting fixed locations or those calculated based on now erroneous assumptions. Never mind if rather than just 1 character name there are a party of 8 and they are scattered around the save. Related to this might be exclusive features or DLC not available for one version or another, which could also be PC settings and control bindings (though this also cuts the other way and by editing console saves you might unlock some features the game responds to that were in the PC version but console does not provide an option to fiddle with under normal circumstances).
If playing editor you might have to figure out or bypass save hashing, and it could be something that is dropped for the console version (modern consoles tend to have said wrappers which if the man making it in the first place is not smoking all the crack would have included as a counter hack and convenience for the devs, anything with some kind of external save management will have something here so pretty much DS for the last handheld, and probably 16 bit and Amiga for consoles though I don't know what the PS1 ultimately had going on as it was early enough to maybe dodge things).
Other times still then yeah completely custom from the ground on up or near as makes no difference.
Do also bear in mind if there are save editors available you might be able to replicate in game items/party members/locations to get to the point where you basically recreate your game. Cheats can also help with this if you can instead power level or otherwise cheat your way back in record time to the point in the game you were at in the console (or vice versa). Harder to go between platforms as your whims take you but I note it anyway.