Some suggestion as I'm an EV owner and electrical engineer. I don't have any EV charger installed in my Airbnbs for guests so those might not be that helpful. Just my thoughts.
First, determine if you want to go with a level 1 or level 2.
Level 1 is essentially a 120V outlet with 12-20A current. Typical 16A draw gives about 1.92kW output, meaning about 20 kWh electricity/charge with a ~10 hr overnight session. So a $3-5 charge for such a session is quite reasonable. All you need is an outlet directly wired to the panel. Don't use outlets that share breaker with other outlets or lights -- it can cause fire or trip breaker.
However as folks worried, a level 1 charger can only get about 20 kWh overnight so might not be very useful (reference: a Tesla battery is in the range of 85-100kWh). So for a faster charge a level 2 charger means more convenience to guests, but requires some investment from host. Also you need to determine if your electric supply capacity can handle this extra ~240V 40A draw.
Level 2 chargers are 240V, typically have 3 types: 16A, 32A and 40A. 32A is quite standard while not all EVs support 40A. I would suggest to have the Wifi enabled ones (like Morec) to track the usage, so charges can be made based on usage. A 240V 32A level 2 charger can give 7.7kW output, meaning about 75kWh per ~10hr overnight charge --- that should get a Tesla battery to ~80% from empty.
Better thing is that with those Wifi chargers you can set to limit time of use -- for example if you have peak hours or different price based on time or insufficient panel capacity.