So far it seems like 10-bit color depth yuv422p10le is only available for AV1 via FFmpeg encoders libaom-av1 and librav1e.
That is not yet with the from experience faster libsvtav1, which currently support pixel formats yuv420p and yuv420p10le.

My AV1 (video only) test run procedure using CinGG loading a 10-bit input file, resulted in 12% smaller file size than with h265. Visually the AV1 output file seemingly is ok, but there are some CinGG output "FFStream::seek I/O errors, seek fails" I don't know what are !?

CinGG (built: Jul 29 2024 01:18:06, rpm on Leap)

Render: File Format: FFMPEG | webm
Video wrench: Compression: av1.webm (libaom?) | pixels: yuv422p10le
Defaults:
   # this codec codes less than one frame per sec
   # and so even a few seconds of video can take
   # a very long time to encode
   cpu-used 5
   row-mt 1
   tiles 2x2
   strict -2
   threads 8

15M    av1_yuv422p10le_LP.webm
** rendered 1780 frames in 184.787 secs, 9.633 fps
FFMPEG::open_decoder: some stream times estimated: /run/media/terje/Videoklipp/Cineform/av1_yuv422p10le_LP.webm
FFMPEG::open_decoder: some stream times estimated: /run/media/terje/Videoklipp/Cineform/av1_yuv422p10le_LP.webm
FFStream::seek: /run/media/terje/Videoklipp/Cineform/av1_yuv422p10le_LP.webm
retry limit, pos=207 tstmp=8280,   err: Input/output error
** seek fail 207, 8280
.....snip
FFStream::seek: /run/media/terje/Videoklipp/Cineform/av1_yuv422p10le_LP.webm
retry limit, pos=87 tstmp=3480,   err: Input/output error
** seek fail 87, 3480

Verificated the output file with FFprobe:

ffprobe -hide_banner av1_yuv422p10le_LP.webm

Input #0, matroska,webm, from 'av1_yuv422p10le_LP.webm':
Metadata:
    ENCODER         : Lavf61.1.100
Duration: 00:01:11.16, start: 0.000000, bitrate: 1709 kb/s
Stream #0:0: Video: av1 (libdav1d) (Professional), yuv422p10le(pc, bt709/unknown/unknown), 1920x1080, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn
      Metadata:
        DURATION        : 00:01:11.160000000