Cross Progression Badges

As far as I'm aware, there isn't really anything that can be done in this case.

As the primary was decided by account level and not gameplay time, it would mean that some badges (Mostly achievement-related) would be lost from the non-primary accounts; according to this source: https://www.ea.com/games/apex-legends/apex-legends/news/cross-progression 

But cosmetics that were gained from Battle Passes and events should not have been lost at all, so that is definitely a bit weird.
Just to confirm, but have you ever unlinked/relinked your platform accounts (e.g., Steam, Xbox, PlayStation) from the EA Account they were connected to?

Keep in mind that if you were hypothetically playing on PC via Steam, and on console with Xbox. But Those platform accounts were linked to different EA Accounts, that they would not be able to merge together.

You could relink for example your Xbox account to the EA Account your Steam is linked to in that case, but you would lose access to the progress you made on Xbox; as it's not linked to the EA Account. (Since all in-game progress is stored on the EA Account)

If you didn't relink or unlink any of your platform accounts, then it's likely something else.
I don't really think EA or Respawn would be able to assist with Cross Progression issues at this point, as it has already rolled out fully for a few years at this point.

But again if you didn't unlink or relink, might be worth to hit up EA Support.