The highest estimate I could find was 167k KIA for Ukraine which aligns with other estimates of 500k total casualties. 1:3 is a fairly standard KIA/casualties estimate for many conflicts.

Ukraine is notoriously tight-lipped about their casualty counts though. As with any conflict, expect inflated/deflated estimates depending on who is stating them.

It's within reason for a 1:3 (up to about 1:5) Ukranian/Russian casualty comparison, given the difference in tactics between the two sides. (Agree or not, Russia historically uses scorched earth and mass to fight wars.)

Unfortunately, you can get high/low estimates from all over the place. The actual numbers may never be known or not known for years after the conflict is over. Orgs that do verified tracking are generally very low with their numbers.

That is a shit way to normalize numbers like that, but averaging out all "officially" reported data and jamming them against rough ratios is all we really have.

(Edit: A recent escalation in Russian casualties is plausible as their access to new/replacement equipment has been reduced significantly. Dig a little into sources that scour satellite photos of tank depots or how sanctions are affecting manufacturing for more info. It's a deep rabbit hole, but data is out there.)