One thing that is important in conquering switchbacks is practicing slow riding/balance drills on flat ground. It's not as fun as riding trails but if you want to improve try these: 1, Ride in an empty parking lot and act as though the painted lines of the parking spaces will give you flat tires if you cross the lines. Ride up into the parking space and slowly turn a 180 while staying in the lines. Get good at both left & right turns. 2, Practice track stands on a SLIGHT uphill. Do not use the brakes but put a little pressure on the pedals to avoid going forward or backwards, stay loose on the bike and move your knees and shoulders to keep your balance as long as you can. Practice both of these over & over, before long it will make switchbacks MUCH easier. If you have the confidence to stop & balance in the corner, maybe ratchet the pedals and crawl around the turn you'll start having more success.
Next, it helps a lot to swing as wide as you can just before the turn, then dive to the inside to straighten out the turn. You want your weight back and concentrate on feathering the rear brake as needed. Practice practice practice. Find someone that can make the turns you want to make & do what they do also!