If I understand correctly, you want a processor with digital outputs that will process and output all material at the native sample rate. Same as me.
John Atkinson did say that the H24D drops all high resolution audio down to near CD quality, but that was only referring to the analogue outputs.
The digital AES outputs are reproduced at native sample rate and bit depth.
Most processors down-sample to 48kHz, but maintain 24 bits where appropriate.
There are a few honorable exceptions, but they're mostly expensive:
- Trinnov AL 32 and AL CI
- JBL Synthesis SDR-75 and 80
- Lyngdorf MP-60 with AES output option
- Arvus H2-4D
All of those will perform immersive / Atmos / DTS-X / 16-channel decoding.
If you only want 7.1 channels output, and your source can do the decoding to LPCM (which they usually can) the field opens up:
AudioPraise VanityPRO
https://audiopraise.com/projects/internal/vanitypro/
Yulen's Black Box / SoundProAudio HDMI to 5AES converter
https://mp.weixin.qq.com/s/0-AfCuR73n9pDbQcyToiVA
Meridian HD621
Meridian HD722
https://www.meridian-audio.info/public/hd621-userguide-a5[1292].pdf
https://www.meridian-audio.com/luxury-home-audio/surround-sound/uhd722/