A module within Microsoft Viva that serves as an enterprise social networking platform. It fosters community building, open dialogue, and knowledge sharing across an organization.
Hello Ernest Wensink
I found a form that some users are using to request access to join groups after the migration: Request access to Finance and Operations Viva Engage Community
Not all groups are listed there, but I noticed that some of the groups you mentioned do appear in this form.
You might consider joining the groups available in that list first. Once your request is accepted, you could then ask to be added to the other groups that are not included in the form.
Alternatively, you may want to ask a colleague for help reaching out to the group admins directly to have you added.
Hope this helps and points you in the right direction.