Charging 2 tesla 3's in same 50 amp circuit in garage

[gfunkdave]

2) change the outlets to 6-20 outlets with new 6-20 adapters for the mobile connector so they will only draw 16A max each. Although again I’m not sure if it’s within code to have two 240V receptacles on the same circuit

Can't have a 6-20 with a breaker that isn't 20A.

OP should just install two wall connectors set up in power sharing mode and be done with it.