Hello all, HTML Canvas APIs couldnt make it on time for this year, apologies for that. But it is going to be a part of UXP 7.0. The ETA is January but it might be slightly longer before PS releases UXP v7.0.
We will be supporting the Webgl 2D apis. For 3D, our recommendation is to use Webview, which will be available in panels, and not just dialogs, in UXP v6.4.