Hi @Daniyel Falk ,
at the end of an Azure Sponsorship in terms of time the subscription will be converted to Pay-As-You-Go.
As far as I know there is not option to extend the Azure Sponsorship if the credits expire and there are still credits unused.
Source: Can I request more time to use my Azure credits?
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten