Migrating from 2 old to 1 new Mac, bringing only 2 of 4 profile/accounts

Bought a new MacBook Air M3 256GB, that will ultimately replace two older Macs, for two people to share. Unsure how best to migrate accounts from our old Macs, which are: 1) MacBook Pro (Mid 2014) with OS Catalina 10.15.7. It has 3 profile/login accounts, 1 being essential (person X), the other two not essential but would like to retain copies of their files/photos in an external drive, and selectively pull those files/photos into newest Mac later. This machine’s drive space is is essentially maxed out.  2) MacBook Air (2017) with OS Monterey 12.7.4. It has 1 profile/login account (person Y). We bought a Samsung 1TB SSD to help with the backups and migrating if needed. First plugged it into the old Air, and was prompted to format for Mac. Without being given a choice, it used NTFS. Then we used it for a Time Machine backup on the Air, before learning that the Pro with Catalina cannot use same file format.  Other details: neither of the old Macs have essential 3rd party applications that need moved to the new Air. Both persons utilize iCloud for backing up desktop/docs/photos, but person X account is not allowing more photos, presumably maxed out. Given there are two Apple ID’s involved, unsure if we will need to choose one as the master for the new Air. So, my question is, assuming I wipe the external SSD, then reformat so it works with both old Macs, and knowing I only want one of three profile/login accounts from the Pro moved to the new Air, what is the best approach to migration? The Migration Assistant seems like it will bring too much to the new Air. Whereas selective copy/pasting of directories would take an eternity. Is Time Machine the best option for both migrations? Or, is it as simple as creating two new profiles in the new Air, then each logging into their respective iCloud accounts to obtain access to most of the essentials, then copy/paste anything that's missing?