Although parent asking for titanium for the feeling, so maybe something in-between would be fine? Lightweight material inside and structurally, but titanium or something else as the "skin".
I don't think a titanium coating over something else is going to deliver that.
I think the reason titanium glasses feel nice is primarily because they have minimal contact with your skin and very low mass.
My frames weigh 6 grams, with lenses they're 14 grams. The Meta Ray Bans are 50 grams. If you could make the frames from pure helium they still wouldn't feel close.
I assume the poster above imagined the something inside could just be voids, like a tiny aircraft. But yes, some kind of low density filler could also add some stability in areas you don't want mass metal but also don't have electronics or battery "cargo".
