I am currently trying to go down a similar road. I sold my 34 lb. Enduro bike to purchase a new Tallboy 4 frame. I am expecting my custom build to be around 28/29 lbs. The only issue is my frame is now two weeks over due. I don’t ride any trails with extended rough sections, and I need all the climbing efficiency I can get. I hope you can find a bike that fits your needs. I myself like the idea of downcountry.