I stretched most of my life, 3x30 seconds per stretch, not much in theme of results.
A few years ago, hurt my back and i started stretching, mostly lower body, holding 6-10 minutes per stretch.
After a few weeks, i started to see good results, and now i do it a few times a week.
A few your body stretched, mainly while driving, a couple of minutes each.
But stretching alone wasn't enough, for example hip muscles so I could squat way down (no weights)
So i started to go thru the motion, not quite forcing, and in a few days, i could squat pretty low.
Not sure if this is mobility.
Anyway, I'm in the camp that stretching allows me to do things easier, like climbing.
I don't believe it helps with injury protection.
But lifting heavy definitely prevents injuries, obviously up to a point