The WebKit commit is over 8 months old already: "Enable WebGL2 by default", Sep 14, 2020 – from
https://trac.webkit.org/changeset/267027/webkitCanIUse reports that it's only available in Safari Technology Preview for now, which is a macOS program: https://www.caniuse.com/webgl2
With WWDC 2021 only ~9 days away, one can hope that they'll announce its support on all platforms in the next major release. If it was already "good enough" last September…