if what you say is correct that Putin has already declared WW3...

if what you say is correct that Putin has already declared WW3 then why is only Russia and Ukraine on the front line both backed by their supporters ?
What other countries have declared war on either side?
When will they resort to using all available weapons as in a world war?
There is no problem with backers on either side supporting their cause. The point is using actual troops to support Ukraine or Russia, not volunteers or mercenaries, would escalate the conflict to a higher level.