Microsoft seems to distinguish administrator and architect by the relative level of professional experience:
-The Azure Administrator cert is considered 'Associate' level, while Microsoft Certified Azure Solutions Architects fall under the 'Expert' label.
Prepare for Preparing for and taking the Microsoft Azure Fundamenta Exam. You will get the speed with the core concepts relating to Microsoft's cloud. Once you have this entry-level certification under your belt, you'll be better equipped to make a decision regarding your desired career path.
Candidates for the Azure Solutions Architect Expert certification should have subject matter expertise in designing and implementing solutions that run on Microsoft Azure, including aspects like compute, network, storage, and security.
Responsibilities for this role include advising stakeholders and translating business requirements into secure, scalable, and reliable cloud solutions.
I hope this information helps.