Spoke to couple of Samsung Plaza outlets - they saying that Frame will remain an online-only model and they'll never get it in showroom. Is Samsung expecting people to do a blind buy for a 1.4L 65 in TV?
Testing is also important because even if TCL or Vu mention 400 nits in specs, there's no guarantee that they are hitting that in usage in accurate modes.
If you check on Rtings, TCL Series 5 barely doesn't even hit 300 nits in HDR mode. Infact, it's brighter in SDR modes than HDR, where it hits 320 nits or so.
So in Frame 2020, you're getting tested performance that's bare minimum for impactful HDR.