Hi, I did a quick and naive reverse engineering and I found a hacky workaround everyone can apply by herself. Opsgenie does not store the colors server side but only somewhere in browser storage, i.e. each person/browser see different colors and they are persisted in their browsers.
So if you deleted site data and re-login, you would get a new set of colors assigned. They might and probably will be bad again, for example 2 green, 2 red, 1 yellow transformed to 2 red, 2 yellow, 1 green, but my account got at least a unique color, which is good enough for me for now. You can try to repeat the steps to get better ones.
I think it might be only a poor colors assignment algorithm and for a local fix on a few lines in frontend code, then force reset the colors for everyone e.g by using a different key in storage and ignore the old one with a tiny leak. This might improve the user experience a lot, probably classic low hanging fruit for a few hours...
Update: It doesn't work long term in real, the setting expires after some time.
Hitting the same issue. My color clashed with someone with the same starting letter as my first name, it's inconvenient.