Hello Dani Stolarz,
Thanks for your question.
This is possibly because you're in the work tenant.
you may need to contact your organization’s IT or Azure administrator to request the necessary permissions to perform the actions you need within the current Azure subscription.
If you want to transfer the billing ownership, you need to follow the steps in Transfer billing ownership of an Azure subscription to another account. To transfer the subscription to a different directory.
If you want to keep the existing billing ownership, you need to Associate or add an Azure subscription to your Azure Active Directory tenant.
If you have trouble, I would recommend reaching out to the billing/subscription team for support as it is free to create a ticket with them. https://azure.microsoft.com/en-us/support
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola