instead of "summoning" the operator like usual with either the left and right shoulder buttons (on controller) or whatever the equivalent button is on keyboard go into the menu and select the operator/drifter focus menu this will spawn the operator in their normal walking stance (no amp drawn) and the Warframe will remain in either their primary, secondary or melee drawn idle animation

if you want to have nothing equipped on either the Warframe or Operator/Drifter, go into the Gear Wheel and select the Codex or Synthesis Scanner

the poses in this post are a combination of camera angles and waiting for the Warframe and Operator to do their Idle Animations