@PhatParakeetAs long as both platform accounts are under the same EA Account, cross progression will be able to take affect.
Unlinking and re-linking platform accounts from one EA Profile to another can result to loss of progression since all the data is saved in that specific account.
Any secondary Apex Legends account made after October 20th-26th for the same EA Account will not be eligible for cross progression.
If you'd like more information on cross progression, you can check this quick guide:
https://answers.ea.com/t5/General-Discussion/A-Quick-Guide-to-Apex-Legends-Cross-Progression/m-p/13148659#M242801