If the new computer is going to be the Apple Silicon M1 Equipped Computer - would suggest Only Migrating the User Account and nothing more.
1 - Apple Silicon with either Big Sur macOS 11 or Monterey macOS 12 Only Support everything 64 bit and there is no workaround.
2 - Issues that may exist on the older computer will be migrated to the New Computer. This would badly pollute the new Original and Pristine installation of the new OS.
3 - Applications, extensions and Software Drivers may or may not even work on the new computer.
4 - IMHO - it would be best to only install new application etc Directly from the Developer or the Apple Apps Store.
5 - Due Diligence on New Applications and make sure they are Monterey / Big Sur compatible and factor in the ARMs CPU of the Apple Silicon Computer
6 - iCloud was designed as means to have files on iCloud so other devices, owned by the user, can access the same files on all other devices. Further, changes to a file on device # 1 will be reflected on all other devices.
iCloud is not designed or intended to work like an External Drive to archive data. That should be achieved by a Time Machine Backup.
For good measure - Do you have a Rescue Plan In-Place. This comprises having 3 Backups using 2 methods and 1 Off Site incase of Theft, Loss or Natural Disasters.
A Time Machine Backup is very useful and can be used to Revert to Previous Working macOS.
For additional purposes - two Tested Bootable Clones each to separate external drives. This is insurance incase. At least one Tested Clone and / or Time Machine Backup should be Off - Site