There's nothing *wrong* with it, I have the same plug on my dryer. It's just that houses made before about 1997/1996 have 10-30s and those after have 14-30s. Both do 30 Amps (24 for a Tesla, normal 80% for continuous charging load...).
Which is why it's a good idea to have both the 14-30 and 10-30 adapters if you go places (beach houses, friends' houses, etc.) where you might need to plug into a dryer socket.
I, personally, have an extension cord (14-50), which can use the 14-30 directly, and an adapter for *that* to plug into that makes it work with a 10-30, which means about the only adapter I need for the UMC is the 14-50 that comes with it to connect to the extension cord.
Big fan of the cords and adapters from EVSE Adapters here:
Adapters for Tesla
Only thing to remember when using the UMC with the 14-50 and their adapters on the extension cord is that you do need to manually adjust the car to whatever the actual max load is (24 Amps here), as using the 14-50 plug on the UMC tells the car you have 40 Amps, when you might not.
As for your personal dryer socket being 'obsolete', I'd just plug in your UMC with the adapter, and start charging at 12 Amps or so, and increase it a bit at a time up to 24 and be sure nothing gets warm and the UMC doesn't complain, to test it out.
But for a permanent setup, a longterm overnight charge of 12-15 Amps should be enough to fill you up!