It was not the solution.
disconneting after a few day even more then ever.
I'm almost giving and move to HomeAssistant

I have managed that mqtt is stable, for now for 5 days on a row.
I have put mqtt in a docker and used this config:

persistence true
allow_anonymous true
password_file /mosquitto/config/passwd
listener 1883
log_type all
#log_type information
#log_type notice
#log_type error
#log_type warning
log ...

Did you manage to solve the problem.
I have the same problem it runs for a week and then several disconnect errors:
Line 1: 2022-12-29T11:24:39: Client Domoticz-MQTT-AutoDiscoverf6d6e1f2-d267-4215-a684-d536c912910c33 closed its connection.
Line 4: 2022-12-29T11:26:35: Client Domoticz-MQTT ...