Yep, that is a well known issue, see this discussion for a workaround: https://forum.qubes-os.org/t/improving-white-background-systray-icons-for-dark-themes
I ended up not doing what is suggested, and made forks of all things that use icons in Qubes instead to mutilate those icons however I want, lol. Now it’s almost decent enough for me to even publish sometime 