Not too sure how effective this is tho, as a solution.
It seems to me like a diplomatic escalation in the sense that banning the Russian ambassador from attending this commemoration event gives Putin something to instrumentalise anyways, at least for internal consumption. In the same time this move does not apply any kind of actual pressure on Russia. So I honestly don't know what good can come out of this move.
This is not exactly what you asked for, but it's the closest thing I can think of. The Forensic Architecture site has some accurate info for Gaza, Palestine but they date back to 2024. Still, I think it's worth keeping an eye out for any new investigation they might do.
A Cartography of a Genocide