It is, I am RWD owner.

438KM is the EPA standard, which is considered the more conservative standard compared to WLTP,  but it is slightly closer to real world range.
It mainly depends on your route, traffic, weather, elevation and driving behavior.
If you're full on highway with fixed speed at around 100-110kmh, I think its not difficult to hit 500km range.
If you're on daily city drive with stop and go traffic, especially lots of short distance travel, you'll likely see a range of only 300km++.

I'm currently living in Sri Petaling area with daily commute bringing kids go and back from childcare center, and most of the trips are very short distance. My 100% > 20% gets me roughly 250km-280km of range only. FYI my daily route is considered very unoptimized for fuel or electricity consumption, even last time with my Honda Civic also getting around 250km only for ~RM65-70 tank of petrol.

Theoretically, yes. But also do take into account that EV are a lot heavier than ICE counterparts.
For my case, Model 3 RWD is more than 400kg heavier than Civic and that kind of offset the efficiency of EV especially in very short trips with lots of traffic. The car has to repeatedly push a stationery 1760kg object to move forward and stop, not to mention in elevated roads (and we also have lots of speed bumps).

In the highway, do notice that I specified "fixed 100-110kmh" speed. Anything above that or any sudden acceleration, you'll lose battery SoC a lot faster. The key is to stay on constant speed and minimize sudden accelerations, then your range will be closer or even better than the rated range. Since switching to EV, my foot has became so gentle nowadays.

Tesla's est. range is off by quite a lot if you're referring to WLTP. I am also quite puzzled why did Tesla display WLTP on their MY website but using EPA in their car. Should just standardize it to reduce the misaligned expectations from customer. I guess they use WLTP to make their cars ranges look better on paper compared to the competitions.

The final boss of Tesla promos

https://www.instagram.com/p/DCERn2Xpln4/?ut...g_web_copy_link

PM me to know more.