Okay, paired but not connected.
That is not a Opensuse specific problem it seems: Reddit - Dive into anything
Are you using the keyboard also for another system? In that case you might need Dual boot pairing
On Bluetooth keyboard I read:
To automatically connect the keyboard after a reboot, see Bluetooth#Auto power-on after boot.
But I see Tumbleweed does not have /etc/bluetooth/main.conf, but something like that is needed.