Full details on the differences that can be found in this Fallout 4 Xbox Series X FPS Boost vs 60fps Mod comparison of the multiple options from a visual, and or tech analysis angle.
Fallout 4 on Switch 2 offers 30fps, 40fps, and 60fps modes, with graphics settings differing from PS4 and PS5 versions.

Following Fallout 4's anniversary update, Nexus Mods have assebled an Anniversary Collection of existing mods designed to offer a free refresh as an alternative

A decade on from its Game of the Year-winning triumph, Todd Howard reminisces on how Fallout 4 changed Bethesda Game Studios, its TV show adaptation and playtesting The Elder Scrolls 6.
They need to look at Morrowind and see what the progression should have been from there instead of the regression we got with the next 2 games. They weren’t horrible games but they could have been so much more.
Fallout 4 just felt too streamlined and accessible to me, the perk system was not as fun as it was in Fallout 3, not saying Fallout 3 didn't have issues but 4 just felt like a complete step back.
So the part where you just sold the same games for the last 10 years while you focused on 76 and merch, was not a reset from the "creative" aspect eh? How very Todd of you.
I bought Fallout 4 (I loved Fallout 3) at launch and I couldn't bring myself to finish it or even get close to finishing it. It was soooo damned boring and bland. I played on a very hard difficulty and I had hundreds of stimpaks. One of the only games I've played for a while and not ended up finishing it. I hated it. Just flat out hated it.
such a huge difference. big L for the boost version here
So mod is 4k60fps, FPS boost is 1080p 60fps.
So I guess obviously the mod is specific to Fallout 4, whereas game boost will effectively drop the resolution until 60fps is achieved, but this is system level.
Clever stuff, you could run the Skyrim 60fps mod and keep trophies with a trick, I wonder if same can be done here?
This game looked dated when it was released and not looking much better.