GCSM is currently NOT working with New Outlook (Web). The Microsoft announcement only affects the old (free) Mail & Calendar apps, which are pre-installed on Windows 11. see the content of the links provided below: These changes will not affect your organization’s use of classic Outlook for Windows.
In parallel, we have a feature request to also support the Web version (new Outlook), but the (sparetime) developers need time for it and maybe some more donations to afford this fundamental change, maybe it should be even another fork on this project, because the interface might be completely different
https://sourceforge.net/p/googlesyncmod/feature-requests/280/