I used
XCI_NCA_NSP_v2 and hactool to extract the EXEFS. That will get you the "main" file which is the primary executable for the game.
You'll then need the
Switch IDA Pro loader and follow the installation instructions (as easy as dropping the file in the correct directory for IDA Pro).
And then the big lift is obtaining a copy of IDA Pro that's new enough to support that loader. IDA Pro 7.5 should work. As far as where to get it - you can buy it or find it elsewhere
That is the limit of the help I'm able to provide on that point.
Then you can open the "main" file with the ida64.exe (you have to run the 64-bit executable as the plain ida.exe isn't going to be able to run the Switch loader/disassemble the main file) as an ARM little endian:
View attachment 358635
Then the world is your oyster. Have at it.