I agree it would be useful to discuss the buffering issue with Apple Techs
but, our only path to those Techs is via a Trouble Request, first with Apple Support(online or phone) with whom 'we may request' sending it up the Flag Pole' to see if our Concern will Fly.
I did that late Spring 2023 but did
not receive a response even though
the Apple Rep and I had alike training
and experience as Electronics Techs.
Just to be sure, this discussion platform is not monitored by Apple.
Contacting Apple Support may be
your only Path to Resolution.
My buffering experiences were much
like yours, Apple buffered more than
my other Streaming Services, beginning with AppleTV+ Launch in
my AppleTV 4k OS. We Users had
zero control over THAT change to our AppleTV 4k service.
I used 3-steps to resolve buffering on my AppleTV 4k: 1)turned off all
AppleTV features I do not use, especially 'Background App Refresh',
AirPlay and HomeKit, Accessibility,
Auto Update Apps, Auto Install Apps,
Podcasts, Fitness and SIRI.
2) I Klein Tested all my Ethernet Cables and Ports AND bought latest HDMI Cables.
3) Verified my ISP-Throughput with
my ISP Service Rep(a rather subjective test due to, most, Service
Rep ignorance beyond their training
and ISP Reference Subjects.
Buffering Continued. So I added 10Mbps to my ISP Streaming Account - that helped quite a bit but not enough.
I should've known better, but I'd failed to examine my ISP Network
Interface Box on my Outside Wall.
By accident, I noticed that Box was
NOT Bonded to Earth Ground! I called in a 'Emergency Condition'
repair which took 2-Weeks to get a
ISP Tech who knew how to fix that!
That Earth Ground, of course is a
Lightning Protector, but it's also a
Circuit Reference for Signal Input
which, if missing, can lower BandWidth.
Earth Ground was repaired, I had 'less buffering'. So I added another
10Mbps to my ISP Account. Viola!
Now I have zero buffering!
Good Luck! My efforts took only
6-months.
ChipDale