There is no restriction on the number of Challenge accounts you can purchase. As long as you use the same email address for all purchases, you can manage all accounts from the same dashboard.
In the funded (Earning) phase, each trader is limited to a maximum of 10 active Earning accounts at the same time.
If you already have 10 active Earning accounts and pass another Challenge, your upgrade will be queued. You may request activation once one of your existing Earning accounts is terminated.
This structure allows unlimited opportunities at the Challenge level while keeping the funded stage controlled and structured.