I dont think so it will be, you just need to thing about it logically for instance I play on pc its over 329 GB cause it has all presets from low settings to Ultra 4K textures so if you think about it those textures are super heavy in size, the switch will most likely target 720P so the textures high be way lower so i m thinking the game will go around 30 to 40 gigs maybe who knows.
Great question handheld should be a number one priority to the team, as thats how i also play, but Nintendo should add a performance mode on the switch letting the switch overclock its frequency abit more on handheld, I overclocked my normal OG switch and honestly its a great experience on handheld.
Another point the new UE engine will also play a good part and i dont think wildcard would relaunch the game on switch if they weren't confident enough that the game runs good, lets just pray the port is good, even the port we have no is good base cause we know are can even run on poop hardware at a cost but at a stable frame rate.
I m sure this talented team is Panic button or epic games themselves who knows lets see what unfolds in the future
I bought the game on launch fought with the ced soo many times about the game and just got sick of it but happy to see the money i spent was worth it