Avatar/Modeling Help! 2D for transparent effect?

(If this isn’t the correct forum, please direct me to the correct one. I am a bit slow.)

Hello! I am fairly new to blender and modeling, and I’m aware of the transparent quest issue.
I’m trying to model this character’s head (first image), and of course the glass cannot be transparent because the quest can’t render it.
Would something like this Rabbit Helmet (link at end) from roblox work? And if so, how would one recreate it? When put on an avatar, the helmet is still 3D but appears 2D, and has an image on the inside.
If that can’t be helped, how does one make the whole head a png that always faces you?

Any help is appreciated, thanks!

It looks like that model uses inverted face normals to fake an outline or invoke the feeling of “hollowness”, that could work.

This is much harder and unfortunately potentially impossible on Quest, but perhaps with a particle emitter that only ever emits one particle with the Billboarding mode set appropriately.