I've been hoping that Lockhart was still in the works. I'll likely be buying 2 for my sons and sticking with PC for myself.
As far as I know, the NovaMonbasa leak was the first accurate leak for the Anaconda and Lockhart, stating they were to be 12TF and 4TF, respectively, as far back as January 2019. It also stated that they were aiming for $499 and $249 price points. If Sony shoots for $450-500, then I could see MS being comfortable with $299 since it seems they assumed PS5 would be $399.
Lockhart is likely to be Sparkman, leaked by AquariusZi and Komachi, and stated by Komachi to feature RT and VRS support, along with bc for XO. NovaMonbasa said it has RT+MS AI, Zen 2 8c/16t, 12GB GDDR6, and 1TB SSD.
I would love a $249 msrp, but I'm guessing PS5 will be $499 and so Lockhart would be ok at $299. And yes, scaling works just fine from 12TF to 4TF, even without lowering settings. Lockhart is like a X1X with Zen 2 CPU, SSD, and RT+VRS+AI/ML.