But accessibility is critical. There are tools to do things like desaturate pages and apps, and measure contrast.
I write Apple apps, and I make sure that I provide (sometimes, quite verbose) accessibility labels to all my UI elements. There's actually a ton more that can be done, but acc. labels, and respect for dark mode, reduced transparency, and increased contrast, as well as haptics, is usually sufficient.
One thing about providing accessibility strings: They should be translated, as well, if you are localizing.
Here's a really cool tool, that I use: https://michelf.ca/projects/sim-daltonism/
Totally agree. I once did some mandatory training at work (on avoiding discrimination, ironically) where some of the facts needed for a good score were only presented in the audio track and were thus inaccessible to deaf people. I'm partially deaf without my hearing aids so am sensitive to this issue.
Another place where I worked had the bays in its car park marked with a colour of brick that was the same as the main colour if you had a certain type of colour blindness. It's actually how most of us found out that one of our colleagues was colour blind, when he got a complaint about his apparently inconsiderate parking (usually taking two spaces because he couldn't see the markings).
But really, these tools should not be a factor for UI design. They're much better for things like data visualization where you're working wit a lot more colors in a tight space.
If somebody is relying on slight variations in hue to differentiate between background and font color, they've already fucked up.
FWIW, I recommend using the squint test as a really rough metric, try and see if you can use something through your eyelashes as you're squinting.
it sucks to readjust the app if you discover late in the development that the palette is not having enough contrast for some parts of the ui.