Hi Dominic Jack,
Thanks for reaching out to Microsoft Q&A.
did you check if this is the case?
The Owner Role that you have assigned to is in for the resource Group as its showing This Resource. If it was assigned to Subscription then it would have been seen as Subscription(Inherited) in the resource group level.
https://stackoverflow.com/questions/71022177/azure-i-dont-have-permissions-but-i-am-owner
have you created some resources in this subscription hence you cannot create another free trial for studying?
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