It sounds like you're encountering a common issue when creating Teams Events and Online meetings via API. The problem you're describing, where neither the organizer nor the co-organizers can save changes to the meeting options, is indeed a known limitation.
Currently, the Microsoft Graph API for creating online meetings does not support editing meeting options directly through the Teams frontend once the meeting is created. This means that even though you can access the Meeting Options page and toggle settings, the save button remains disabled because the API does not pass the necessary parameters to enable these changes.
So, when creating the meeting via API, ensure that all necessary meeting options are set correctly at the time of creation. This includes settings like who can bypass the lobby, who can present, and other meeting policies.