NEMA 14-50 maxes out at 32A.
You can do 40A with the NEMA 14-50 wall charger. And 48A with the hardwire wall charger.
To clarify, a NEMA 14-50 outlet can legally/safely deliver a maximum of 40A for an extended period, although it can legally/safely deliver a burst of 50A (for when an appliance starts up). EVSEs should never use the "burst" capability.
Tesla's Gen1 Mobile Connector (which was delivered with older Model S and X vehicles, but never with Model 3s), when plugged into a NEMA 14-50 outlet, can deliver a maximum of 40A, the same as the NEMA 14-50 outlet; however, as others have noted, SR/SR+/MR Model 3s are limited to 32A, so that's all you'd see when charging with them.
Tesla's Gen2 Mobile Connector (which comes with all Model 3s and newer Model S and X vehicles), when plugged into a NEMA 14-50 outlet, can deliver a maximum of 32A.
Tesla has sold a few Wall Connectors with NEMA 14-50 plugs. I'm not 100% positive, but I believe this version of the Wall Connector maxes out at 40A. Hard-wired Wall Connectors can deliver much more than that (something like 64A or 80A; I don't know the precise limit, offhand),
if it's wired up to a circuit capable of delivering that much power. The Wall Connector has DIP switches or a dial internally (depending on its age) to set its amperage limit. Many third-party EVSEs can also plug into NEMA 14-50 outlets, but their limits vary depending on the make and model.
There's never a problem with a power consumer (like a Tesla) pulling less power than the circuit can handle; you can dial down the amperage that a Tesla draws, even if every other part of the circuit can deliver more power. Something in that circuit, though, imposes a limit. Cars and EVSEs are designed with enough "smarts" to know their own limits and prevent exceeding them -- so the car and EVSE will negotiate a charge rate, which will be the
minimum of what the two devices support or are configured to use. Circuit breakers impose their limit in a cruder way, by shutting off power if too much is demanded. Wiring can overheat and catch fire if its limit is exceeded, which is why it's critical to match its capacity to everything else in the circuit.