Shampoo is not the enemy. Undiluted shampoo scrubbed straight into dry ends is. Three small changes make wash day far gentler.
Dilute first
Mix one part shampoo with one part water in a cup. It spreads more evenly and rinses out with far less friction.
Lower the temperature
Lukewarm water for the wash, cool water for the final rinse to close the cuticle and lock in softness.
Pre-condition the ends
Apply a light conditioner to the ends before you shampoo. It creates a barrier, so the cleanser reaches the scalp and leaves the lengths alone.
One more habit worth keeping: never detangle wet hair with a fine comb. Fingers first, wide-tooth comb second.