Do you have to be always connected to your node?

1. Power on your node in the morning. It is not connected to any smartphone or PC via BT/USB/HTTP;
2. In the evening, connect to it via BT/USB/HTTP;
3. Access all messages received in Primary channel and/or DMs.

Is it possible? How many messages does a node store in it's internal memory? How to access them via terminal? If node is restarted, are they erased?

I have a Heltec V3. In Meshtatsic CLI there's --listen option, but it's about receiving new packages in real time.