Force FileVault to use 256-bit key encryption Is there a way to use 256-bit key encryption for macOS system?

I’ve tried formatting system partition myself with bigger key size APFS, but macOS installer actually reverted this as it asks for user password now on login screen, not “disk password” on boot.
Most documentation I'm finding seems to indicate that the key's used in macOS 10.9 and higher use a 256 bit key by default.


  Encryption and authentication support
  
  FileVault 2 uses the Advanced
  Encryption Standard (AES) encryption algorithm, which delivers robust
  protection for stored data. Until mid-2013, it only supported the use
  of 128-bit keys, not 256-bit keys. Although 128-bit keys are
  technically acceptable in many environments, organizations are rapidly
  moving toward 256-bit keys to thwart emerging threats.
  
  The latest versions of Mac OS X, starting with 10.9, support 256-bit
  AES keys, so organizations wishing to enable FileVault 2 on legacy
  systems should be cautious about the 128-bit key strength present in
  older Mac OS X versions, Lion (10.7) and Mountain Lion (10.8).


Reference: Apple FileVault 2: Full disk encryption software overview

This PDF and the Wikipedia page seem to indicate this as well.


macOS Security - Overview for IT 2018
Wikipedia - FileVault