KDE Connect stopped working

Hello everybody at KDE,
I am running Funtoo 1.4 since 2020 with KDE 5.16.1. I also have KDE Connect installed under the Funtoo system; the version is 1.3.4.
I have two Android phones, a Xiaomi MiMax2 from 2017 with Android 7 and a Realme 8 from 2022 with Android 13. On both devices is KDE connect 1.30.1 installed from the Google Play Store.
All devices were connecting to each other without problems for 4 years (since April 2020 when I installed the Funtoo system on my computer).
But meanwhile, some weeks ago, the Realme Phone and the Funtoo computer can not find each other anymore. Re-installing the app on the Realme does not help. The app has all permissions possible.
Anyhow, the old Xiaomi and the Funtoo conputer find each other without any problem.
Is it the app not working properly? Is this an Android 13 issue? The Android version shows a date from April 5th 2024 which seems to be fairly up-to-date.
Can anyone confirm similar problems?
Edit: The two phones can connect to each other, no problem with that.