I assume you were able to navigate to https://make.powerapps.com/ and to switch to the Dev Environment that you created?
Can you see a page that looks like this? A developer environment won't require a license so as mmbr1606 suggested, you might have authenticated using a saved Microsoft username that isn't your @learnwithpowerup.onmicrosoft.com address. Therefore, logging in via an in-private/incognito session may help.
this can be solved when you use an in private window, try again this way.
if this does not solve your issue let me know.
If my answer was helpful and it solved your issue please mark it as verified answer. If it helped but did not solve please consider giving me a like :)
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