@Jenslöv, Niklas, Thanks for posting in Q&A.
For the question, how can version 124.0.2478.50 (247805005) be installed on our devices in the first place?
If you deploy Edge from Managed Google Play via Intune, the app will auto update on targeted device.
https://learn.microsoft.com/en-us/mem/intune/apps/apps-add#app-types-in-microsoft-intune
As for SSO issue on Edge, I have tag Microsoft Edge and Microsoft Entra ID on this case, please wait for the support to help.
Thanks for your kind understanding.
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.