I've got a jewelry hack that might work if you're OK with individual jewelry items being outside an actual jewelry bag, though I sometimes put multiples of these inside one of many different Japanese MUJI bags. I save the protective foam mesh that you find around some fancy or exotic fruits. They stretch a bit and provide a nice cushion. Put each necklace inside one and hand-tie a knot or use a twisty tie or a hinged, plastic bag clip at both ends to make a closed-end tube shape. I also take small sheets of bubble wrap to roll each necklace into ....best for carry-on bags becauseTSA tends to open bags with bubble wrap inside. Muji come is so many sizes and are virtually weightless. Lastly, I save hotel shower caps for wrapping earrings individually. By the time you have rolled it around and around the item, there's a bit of padding created by all the layers.
MOMA Design stores and Retail in Japan have the most size and shape choices. MOMA online has this one:
https://www.momastore.org/museum/mom...63_26712_68809