Apologies for the delayed response! From your issue description I understand you have verification issue on Outlook account and you're wanting to complete the learn modules with another (personal) account.
I believe you're practicing these modules:
https://video2.skills-academy.com/certifications/exams/az-900/
https://video2.skills-academy.com/training/paths/azure-fundamentals-describe-azure-architecture-services/
You need have a Microsoft account to sign in with. However, you can link your personal account on Microsoft Learn. You can have up to five school/work accounts and one personal account linked to your profile.
if feasible, you may consider creating a new Outlook account for practicing the labs.
Checkout the FAQs here: https://video2.skills-academy.com/training/support/faq?pivots=profile
Can I merge two profiles of mine into one? and What should I do if I lost access to my Learn profile? The sandbox works independently from your regular subscriptions. While you're practicing and learning with Microsoft Learn, you can use the sandbox, which are free.
"Online authentication is the only method to verify ownership of a Learn profile. If you have lost access to the account associated with your Learn profile and no longer have access to your Learn profile, you will have to recover the authentication account through its recovery process to regain access to your Learn profile. To avoid this situation, if you only have a work/school account linked to your Learn profile, consider also linking your personal account to your Learn profile. You can "Add account" on the Learn profile settings page. Note that Microsoft Learn will not manage Learn profiles on behalf of users."
Happy learning!