Yes, it is legal to use conduit as a protective shield (in this case you are not using it as a wiring method). In this case the conduit fill is irrelevant, it just needs to fit (and be 4 cables or less due to derate). You will need 3/4 conduit or you will lose your mind trying to fit it. Also you will need 4x4 junction boxes at the bottom because of wire-fill rules. (4 wires, grounds and yoke = 7 units or 14 cubic inches at 14AWG, 15.75 c.i. at 12AWG).
But why not just use it as a wiring method?
Put a junction box at the top of the conduit.
Probably cheaper this way. You're getting to use 1/2" conduit instead of 3/4". Replacing 8-10 feet of thick Romex with same length of single conductor THWN-2. One extra 2x4" junction box ($1.29), some ground screws ($1 for a bunch), and some Romex clamps ($3 for 5).
This part happens at a comfortable desk.
First, the upper junction box (4x4) has a hole tapped for a 10-32 screw. This takes your ground screw. Attach an 8" pigtail to that.
Assuming you've already fit and bent the conduit lengths correctly, assemble the upper and lower (2x4) junction boxes to the conduit.
Also knock out a hole (or 2 holes) for entry and exit of the Romex, and stick a Romex clamp in each of the holes, mounted so you can tighten the screws later. Some Romex clamps allow two Romex in the same hole, that's fine.
Now, cut two THWN-2 single wires the right length for the run between boxes, with ~6" slack on each end. Strip the ends, then take one wire and tape about the last 3" black on both ends. That's the hot. This type of marking is legal for white wires only. That's why you buy white.
Wire up the receptacle on the bench.
Now back to the wall.
Now, physically mount the thing on the wall. Feel free to do all the conduit drops in the same way. You can bolt in the receptacle once the box is mounted. Use short 6-32 screws in front of a conduit entry, the long ones will bottom out. Most wire strippers have a cut-a-screw feature.
Lastly, get your Romex and connect each of the upper junction boxes. Wire nut all the hots together, all the neutrals and all the grounds including the ground from the box itself. The steel EMT will carry ground to the lower box, then the receptacle will get ground via the steel ears on the yoke.
If you want the first receptacle to be GFCI, do all the above but use a 4x4 junction box in the lower first position (this is for legally required cubic inches). Use a GFCI cover on that box. Run 2 more wires up the conduit - two for LINE, two for LOAD. Tape them creatively to distinguish them.