Hey Moritz,
Sorry to hear that! The Scale plan is designed for larger companies that either have multiple IPs/products they manage under the same roof and/or B2B use cases.
When you started the multi-domain feature was not yet available.
One way to solve it with 2 Essentials projects is to use webhooks to sync them up. This gets a bit complicated when you deal with profile/credential updates.
I will talk to the team if we can find a different solution for you.