The only thing I've learned about this industry is that the answer to every question is "it depends." Hopefully whoever you're going through is a solid company that will actually take the time to resolve the "depends" in the way you need and can explain it to you.
But at a high level, here's an example of a solar-ready 200A main panel that is available at Home Depot. You can see it's relatively cheap at about $150. This is "solar ready" since it's got an oversized busbar and has slots ready for CTs. I think in some cases these panels are also fit for line-side shenanigans to splice in solar... although you shouldn't need that since you have Powerwalls.
Square D Homeline 200 Amp 20-Space 40-Circuit Outdoor Ring-Type Semi-Flush Mount Solar-Ready Main Breaker Plug-On Neutral CSED-SC2040M200PF - The Home Depot
The "It depends" part about the total cost of replacement includes factors like:
1) "Like for Like". Maybe your new main service panel is the same amp-rating as your old one. Or, you're increasing service size... which is a huge headache compared to if you're just putting in a "like for like" replacement. I
made this thread to explain the headache I encountered because of PG&E and my gas riser. If you need to lift and shift your main panel along with extending your underground service entry, you could be looking at a $20,000 slap in the face (that was what I was quoted).
2) Jurisdiction. I don't know where Teslaland is, but every PoCo has funny rules and may have other requirements around whether this main panel would work for you.
3) Service. If you have above-ground service you may need an additional tunnel kit.
4) Mounting. The link I provided is for a semi/flush mount. Maybe you need a surface mount box which I think costs a bit extra.
5) Finishing. The actual physical dimensions of your old box panel be different than the new panel. Some exterior work/stucco/blah could be required on top of the actual work to put in the main panel
6) Permitting. I think it's recommended for your contractor to submit the permit to replace the main panel as a separate exercise than the PV and ESS. This means a separate set of doc fees, inspection fees, meter release, and disconnect
Anyway, best case, this is "free" and part of your bid. Worst case it's a $20,000 deal-killer. Good luck.