When a system is suspended (put into sleep) and later resumed, a bluetooth mouse doesn’t reconnect automatically.
Note: This might only affect certain systems/mice, not all.
The problem started around kernel-5.18.5-200.fc36. More details are not yet known.
In GNOME, it is sufficient to open Settings → Bluetooth dialog and the mouse should reconnect shortly (you can also manually enable the connection in that dialog). The easiest approach is to type “bluetooth” in the GNOME overview, which should offer you to open this settings panel directly.
Another workaround is to restart the bluetooth service from the terminal:
systemctl restart bluetooth