A much more significant problem to me is when streaming services don't preserve the original aspect ratio. Like cropping to make a 4:3 show 16:9 or a 2.35:1 movie 16:9.
It wouldn't be so bad if it was just the entirely (or mostly) CG scenes that weren't composited to widescreen, but it was also stuff like when they shot one of their plasma weapons. The DVD releases wound up switching to really nasty upscales of broadcast footage cropped to 16x9 for just those shots. Was particularly bad in the first season.
And fitting for the topic, there is a Matrix - Open Matte trailer on Youtube, was never broadcast in that form, but an interesting watch at what is in the full picture:
https://buffy.fandom.com/wiki/User_blog:BuffyHD/What%27s_Wro...
Now that Matrix trailer is how I remember it from my 3 visits to the cinema and dozens of times on VHS! Much less green tint.
HBO didn't roll out 4K content until months later, though, so things may have improved since then.