I will probably be repeating some from here:
1. Cold tire pressure - add 2 PSI to label probably set to cold to 44 psi.
2. I would check alignment to make sure no wheel dragging.
3. Check for dragging brake or not adjusted properly.
4. Ignore the mileage range on the top of the screen. Switch to percentage. That mileage is an EPA estimated range. The real range based on elevation and traffic is seen using the range graph in the lower menu bar (if you have the latest software update). Selecting that will show estimated range based o 5/15/30 miles. Try 30. However, if all driving city and stop and go range will be reduced just like an ICE car. On the highway, at a constant cruise I will often observe a range that exceeds the EPA number on the top of the screen.
As I'm sure you are aware, the performance model has the lowest range. This is primarily caused by the inertia and energy needed to turn the larger heavier performance wheels and tires. That is why the 18" wheels have the best range. Beware of potholes. The sidewalls on the performance car are narrow and the load raring is the lowest on those tires per tire rack.com
5. When preheating the car for departure, observe not only cabin temperature but battery temperature. The cabin will heat before the battery is up to best temp. You will note either a snowflake on the screen next to the battery symbol or on your app, three wavy heat lines (similar to the seat heat symbols). They shay battery is still being preheated and the charge scale on your app will also be amber and turn green once up to temperature. You can drive cold but range and regenerative braking will be reduced.
If you car is only a few weeks old it will be easy to sell if you truly hate it. here is the thing, an ICE car never gets the published mileage either but no one thinks about it since there is a gas station on every corner. The car had excellent software to determine arrival charge. It allows for traffic and elevation changes. Use the navigation often. I have found it usually is within 1% from starting estimate PROVIDED you follow speed limits. Having driven from coast to coast, when trying for the next stop and exceeding the limit I could see arrival charge dropping (no different than an ICE car). If reduced say 2 mph below limit it will start to increase. The car is quite smart and if using navigation and speeding it will at some point flash a message saying "Reduce speed to XX to make next charging stop).
You can really enhance range by when accelerating not feeling it. The Tesla app when judging driving score emphasized this. If you feel the acceleration you're too aggressive.
Leave the car plugged in until ready to go somewhere. If you charge then park (like getting gas and parking) there will be consumption while parked like from Sentry (about 1 mph/hour) so overnight could see 12 or more up to 24/day. Constantly checking car status uses battery as well.
In the midwest, you will see preheating the battery raise range right on your app. I will often see a 5-7 mile range increase from the projected range (EPA) and the charge range estimate as things warm.
You own the most advanced car in the World. One year from now, the software updates will give you a car that did not exist today.
Last - let the car sleep over three hours. This allows the cars BMC's to balance the cells. A good daily charge is 80%. As you approach 90% regenerative braking is reduced. Past 90% it is quite low. If you have a setting (it may be gone on your vintage) in the drive settings check for regenerative braking set to normal not low. Your brakes will thank you and your range will too. You can observe the car regenerating or using battery by the gray/green scale top left of screen. If lots of dots on top left that is the area no regenerative available if charged to say 95 rom 100%.
BTW, my previous ICE car (with stop/start) would see 34 MPG highway and 14 city. Never saw 34 published 34 and 19 city no way. But then I drove for fun. If you sell the car now you can get more than you paid and the buyer will thank you.