Atmos (or any multi-channel not working during internet streaming + video quality

if they are full 4k bluray remuxes, they can easily exceed 100mb.

~200 would be a safe minimum bandwidth for direct play 4k/uhd/hdr remuxes.

check through all the plex settings, there is something there, its slightly different on various devices.

apple tv is NOT compatible with truehd/atmos.
it can play streaming atmos (ie eac3+atmos)

the ‘infuse’ app can decode truehd to pcm, but you still lose atmos.

you might want to check out @ Plex, 4k, transcoding, and you if you haven’t.