I believe you are making the mistake many people make, when starting to look at home charging. You are asking the wrong question, in my opinion. The question isnt "how do I get a 14-50 outlet installed in this home?"
The question should be (to an electrician) "How much capacity do I have in my current panel for a 240v Circuit for EV charging"?
If you ask an electrician for a "14-50" they will in general, quote you what is necessary to make that happen, including panel upgrades, etc, if needed. Unless you use your car for an Uber / lyft vehicle, no one "needs" the fastest charging their vehicle can do, which in this case is 48amps or 44-45 miles an hour charge rate, at home.
I have it, but its not worth upgrading a panel for or something.
Let an electrician tell you how much capacity you have, without upgrading the panel. Could be 20 amps, 30 amps, 40 amps. Whatever it is, its likely fast enough for overnight full charging of your EV.
TL ; DR, ask an electrician for a load calculation to find out what capacity you have in your current panel for EV charging, vs "I want a 14-50".