Although Chromium's Metal backend is still work-in-progress, it should be quite stable as of today. Could you please check Chromium Canary whether it has the same issues? If so, please file a bug at https://crbug.com.
BPTC formats are not supported by Apple's OpenGL drivers (see footnote 1) so they can be used only with Metal.
Safari 16 on Monterey and newer uses Metal by default so BPTC formats are available there.
/cc @donmccurdy