Also, a key problem that some of those “ideal” colour choices run into is how many people out there have shockingly bad screens, or half decent screens setup oddly for their lighting environment. What looks more pleasant on my screen and yours, using choices that are not “all over the colour wheel” might result in things not looking different enough on other people's screens. Sometimes it is fine when the colours are next to each other, but not when they are shown alone or on the same display but far apart. The “same display but far apart” can be an issue itself with
really bad displays, with, for example, two colours that look distinct in one corner looking almost identical in another or in the middle.
A milder symptom of the issue is that even for people with good enough screens setup reasonably well, there will be differences between them that compound the fact that we all perceive what is good in colour selections slightly differently to become an obvious example of the adage “you can't please everyone all the time”.
> the license/attribution-requirement is kinda annoying
There might be circumstances where it is a mild inconvenience, but I don't see the attribution clause of CC-BY to be at all arduous. Though I would suggest they change the text to explicitly mention v4 (the link does, but the text doesn't) – earlier versions of the BY licences had an accidental trap that could be used by unpleasantly by legal trolls in some jurisdictions (ref: https://creativecommons.org/2022/02/08/copyleft-trolls/)