When doing restoration on your iPhone, the profile is not restored to it. Depending on the operator providing you with your eSIM profile, it can often be reinstalled by re-using the QR code or the activation code provided initially.
With the Ubigi eSIM profile for example, we advise you to delete the eSIM profile before the restoration (this has no effects on your Ubigi account which remains active), then to reinstall it immediately afterwards by following the instructions here from point 3.
You can then use the Ubigi services again as usual.