McNuggieeeee If you are talking about merging two EA Accounts, it is not possible to merge progress and data of two Apex accounts.
If you are talking about merging your platform accounts with your EA Account, that also isn't possible either, as Cross Progression had already been fully rolled out, (which means that any new linked platform account(s) will access and use the already existing Apex progress and data stored in your EA Account, (if one exists)).
> EA Help | Apex Legends™ Cross Progression
> EA Help | Merging your Apex Legends™ accounts