>So now that h.264, h.265, and AV1 seem to be the three major codecs with hardware support

That'd be h264 (associated patents expired in most of the world), vp9 and av1.

h265 aka HEVC is less common due to dodgy, abusive licensing. Some vendors even disable it with drivers despite hardware support because it is nothing but legal trouble.

I have the feeling that H265 is more prevalent than VP9