When you install a Ubigi eSIM profile, you are invited to create a Ubigi account at the end to finalize the installation process. This means that each time you install an eSIM profile, you will have to create a new Ubigi account. It will not be possible to merge them in one single account.
But no worries! When you switch from a Ubigi eSIM profile to another Ubigi one, the Ubigi application on your device will connect automatically to the associated account (just re-open the application to refresh the display and you will be connected the right account).