I remixed this from m4RT1n>Nate80 (Osmo2/Osmo3). Original Osmo 2 version was left side only. Nate80 swung it around so it would sit on the right side for the Osmo 3 but I had to add much more room for my hand to fit.

The microphone holder with cold shoe mount is from Nate80's remix design https://www.thingiverse.com/thing:3859901/files

I didn't want to simply repost his part here.
I also added some fill and above and below the screw hole for reinforcement.

I fit this based on my hand size and using a Rode VideoMic Go which have a shock mount that requires more extension from the mic arm to avoid it sitting against the back of your hand if you are right handed.

I used a 1/4 -20 rounded bolt. .5 inch length to attach the arm to the Osmo 3.