I hope you don't give up with Etsy, it's my go to for a lot of things now! I've had a completely different experience to a lot of people here - I use it for homewares like ornaments, dried flowers, paintings, cross stitch kits and gaming merchandise and most of what I buy, because of what it is, is unique or handmade. I've never had to return anything, found sellers really make an effort to communicate and the delivery estimates are spot on.
On the flip side, I find Not on the High Street has massively gone downhill and has the same rinse and repeat, boring items for personalisation.
So I guess the difference is in the sort of things people are looking to buy? Or maybe I've just been lucky!
I would also never buy anything via an Instagram advert because they all seem to be cons or dubious 'beauty' products. However, I do follow hundreds of artists who post videos and pictures of themselves creating their products and, as a result, have now bookmarked their various websites/shops (same for Youtube). I also bought a painting on etsy, found out that a video was available on Instagram showing how it was made, and followed the artist that way. I guess this is a bit more work for the seller but, as a buyer, I love seeing the process and this does make me more inclined to buy something. So I echo what others have said about diverse marketing and really highlighting your handmade selling point.
The internet is also fantastic for guides on things like photography, so if you think your pictures might be letting you down something like youtube is great for improving your staging, skills etc rather than paying someone to do it.
Good luck, I hope it picks up!