Blaze Wizard soloing Chaos Vellum

I thought that damage against a physical resist 300% PDR boss would need like 5-10m range... Wait don't tell me that they have 100% elemental ignore like paladins?

Elemental/Physical resistance and PDR are two completely unrelated things. You need % Ignore in order to bypass PDR.
You need around 90% Ignore in order to do your normal damage to Vellum (or close to your normal damage, at least).