Hey @Yuriy Semyenkov thanks for reaching out!
Quick distinction that may help: Organization Admin and Server Admin are separate roles.
For most handovers, Org Admin is what you'll need. It gives full control over your org's projects, members and secrets, and any existing org Admin can promote another member from your organization settings on the free plan.
Server Admin (instance-wide Server Console access) for additional users is a Pro feature, which is why you saw the upgrade prompt. If you need it, our team is happy to help you find the right plan, just let me know!
Thank