I just disabled the Telekom-SIM and re-enabled an outdated Airalo-eSim from last vacation. Got the update in minutes (with WiFi) and it run without any problems. Especially the annoying bug with the network name is gone, but an old problem seems to be back: even if WiFi/WLAN is deaktivatet and I want to use 5G because WLAN is unstable in some places the WLAN gets automatically turned on sometimes.