Suddenly no permissions to do anything anymore in EC2

Hi everyone.

I have the root EC2 account and from one day to the next I cannot do anything anymore in EC2, this started happening end of April :

All the IAM users under that root account had the same problem. I cannot even go and manage IAM users anymore, I litterally have permissions to do nothing anymore. But today one of the IAM user under the root account could access everything, he can see and manage all the VMs .... I'm very confused about this and how to solve it.

All error messages say that I should contact my admin. But this root account is part of the large organization I work for and I have no indication who is the exact admin for me, so that's my main problem. Is this something inside my org that happened ? I read that some permissions changed in AWS early 2023 and access could be lost if you don't move to a new time of permissions or sth ...