I planned to have the main power (plus) to my MPPT switched through the main power switch in my campervan. But someone now told me that the MPPT doesn't like to see solar panels and no battery. When I'm not using the van, the panels are connected, and the battery is disconnected through the main power switch. Is this okay for the MPPT?
Since you have an AGM battery, I would not disconnect the MPPT, which keep the battery always full, but you should the switch to "Storrage Mode" which is some Millivots lower then the Float Voltage.
Do not do this as drawn. As you have it currently, the MPPT will still be providing power to the DC bus after you turn your battery bank off using the main switch, which for obvious reasons would be incredibly dangerous. Additionally, as stated in the manual for all MPPTs, the battery must be connected first, then the PV, and when decommissioning then disconnect the panels first, then the battery.
Either connect the MPPT output directly to the battery, and let your panels keep the battery topped off, or keep the MPPT as shown and add a PV disconnect so that you can turn off the PV input before disconnecting the batteries.
