i'd say tesla's biggest advantage is battery tech, and it needs to learn to make a better car.
its competitors have been perfecting cars for 100 years, and are very quickly gaining ground on the battery tech.
tesla is losing its competitive advantage very quickly
It's not the battery tech itself that's vastly superior, it's their ability to create enough packs to ship over 1M BEVs annually. Other manufacturers are playing catch-up and have even limited sales due to an inability to procure enough battery packs. Tesla's "famous" supply constraint is due to a limited number of auto assembly plants (to date), which will be resolved in 2023. They will no longer be constrained by how many cars the 4 Giga factories can assemble, so the backlog should shrink to zero.
As far as making a better car, many reviewers still put Teslas near top of BEV class. A 2022 Model 3 is gonna (on average) be better than a 2018 product. One can argue they aren't improving their QC fast enough, but professional reviewers still review Tesla favorable (aside from quality issues). I would say the main gripe with Tesla is they're selling a mostly mainstream vehicle (with some notable deficiencies) at luxury car prices. But with the die cast, many other automakers have adopted the same strategy. Good luck with that when a recession hits!
The Reno Giga factory is (was?) a joint venture with Panasonic. IIRC Panasonic wasn't making much money on the arrangement, so they haven't been all that interested in scaling up. I don't know what type of financial arrangements exist between the two firms or what Tesla pays (if anything) to assemble battery packs at its auto assembly plants.