@Lhetos Thanks for posting in our Q&A.
Yes. MFA is currently not supported in multi-app kiosk mode scenarios.
So, it is suggested to use single-app kiosk mode. Configure your devices to use single-app kiosk mode with Microsoft Edge. This setup is simpler and seems less likely to conflict with MFA requirements.
Then review and adjust your conditional access policies to ensure that they allow MFA for logging into Microsoft Dynamics 365 ERP while using Edge in kiosk mode.
Before rolling out the configuration widely, test it with a few users to ensure that they can log in to Microsoft Dynamics 365 ERP via MFA without issues.
Hope it will help.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.