Also, we too have a 14-50 outlet in the garage from when we had only one EV. Used the Tesla mobile adapter and it worked fine (only 32 amps though). When we got our Q8 ETron, I got a NeoCharge splitter with the Tesla and Audi mobile adapters plugged in (Audi would do 40 amps). The Neocharge was nice, worked fine, but the whole thing (splitter and two mobile chargers) seemed a bit kludgy. Then dumped the Model S and got the Air, and used the same setup for a while.
I wanted a dual charger, but they were quite expensive and often bulky.
Finally got a REV+ Dual EV charger. Just plugs in (hardwired available too) to my 14-50 outlet and will charge both cars at the same time (which some don't do and the NeoCharge would not). It's a nice small unit, UL certified, and only took a few minutes to mount (comes with mounting hardware). I *did* have to set the REV+ to 40 amps max (since it's a 50 amp circuit breaker), but that took literally 5 seconds with the app. And, it was considerably less expensive than some other options.
REV+ app has some functionality like schedules, which I don't use but may be useful for some. App is "ok", not the greatest, not the worst, it's "fine". The app mainly connect to the unit via Bluetooth, though you do configure WiFi for firmware updates and remote diagnostics. Personally, I'd be OK w/o the app (as long as I can set max amps drawn somehow), but can see its usefulness for some applications.
Finally, yes, I know hardwired is the best, but since we had a 14-50 already there, with a good quality outlet, and nothing ever even gets warm, just decided to go this route and it works great w/o issue.
If interested,
Vendor link -
https://www.rplusev.com/
Amazon link -
https://www.amazon.com/dp/B0GFHGGPHT?th=1