I see at least eleven, but I think this also has to do with your monitor. This is a bit like comparing the sound quality of different record phono cartridges by listening to a youtube video. It’s not difinitive.
One interesting thing I noticed was that after examining the narrower bars on the left, when I looked back at the two “fat” bars on the right, they suddently were obviously a lot more colors. i.e. I could see the subtle differences I couldn’t see at first.
I’ve heard that no culture had a word for the color “blue” until just a few hundred years ago. And this video about “brown” is truly fascinating. It turns out that language actually filters how we see the world.
https://www.youtube.com/watch?v=wh4aWZRtTwU
You’re exactly correct about the monitor. The color depth of your display driver will have a big effect as well. The comparison to phono carts heard through YouTube is dead on the money.