Wondering if any of you have recommendations for purchasing decent quality flies online. I may try my hand at tying my own when I retire at the end of this year. For now I am looking to purchase flies that are not mass produced in third world sweat shops. I am getting back into fly fishing after a 10+ year hiatus and will be fishing the streams in western NC. Any advice will be greatly appreciated.

I think all flies are still hand made, if any "mass produced" as in machine made, I'm not aware of it.
I do suspect all flies for sale on the web are 3rd world made, maybe better flies than would be tied here at a fraction of the cost. For example Kenya has been exporting millions of fishing flies to Europe, USA, Canada, Australia and Japan since the early 1900s, supplying about 1/3 of all flies used in Europe. So they have established a highly skilled work force that costs much less than the same skill level would cost in USA.
To meet your requirements, I'd recommend you find a local shop that sells only what they tie, and that may be hard because my local shop owner is a great tyer and contracts with other local tyers, yet still sells imports some flies.
If you want to buy online even knowing that the flies are 3rd world, you might buy a 1/2 dozen randomly from several or many retailers and see if any of them are good enough to work as compromise. I've tied most of what I used for about 47 years so can't really recommend an online supplier except to say that others recommend it. (I had to start tying flies as soon as I started fly fishing because buying mail order was just too expensive back then. I did send for all the glossy color catalogs so I could use the pictures as models)
Just another passing thought, I wonder if the people working in those 3rd world shops would be better off not working at all because we boycotted the fly importers? do those countries have "assistance programs" like we do in this country that would pay them better than they could earn working at a wage?