Changing wifi ap is no option for me, since I’m in a corporate environment. The eduroam wifi is usually available on 5GHz and 2.4GHz.
For me installing the driver (not only the firmware blob) of the latest maintained core release seems to have solved the problem.

According to dmesg my wireless card moved between different aps before. Those messages are gone now and wifi isn’t hanging anymore.

Thanks for the link to the core releases!