Russians pay taxes, about 50% of which go directly to paying for a genocidal invasion. They're no different than the soldiers using the weapons they've paid for.
Merely blowing up their oil refineries and power plants is already a kindness that they do not deserve. There is nothing ethically wrong with Ukraine intentionally killing so called Russian "civilians" to collapse the Russian war effort faster.
This is doubly true for the ~1 million Russians who have moved to occupied Ukraine, forcing out the Ukrainian population and stealing their homes in the process. They're clearly war criminals directly participating in genocide.