Once upon a time, I was fairly strong but I couldn't touch my toes. That full deep stretch was just a little beyond me. It always had been, as long as I could remember in my adult life. Throughout years of martial arts and parkour that moderately normal level of flexibility eluded me.
Then I quit my job at Amazon. I was so burned out I ended up taking 6 months off. During that time I mostly hung out around the house. Played with my kid. ... played a ton of Minecraft.
The point is, I wasn't doing any new exercise. I was just doing things other than hunching in a chair all day. And just before I started a new job I discovered that I could touch my toes again!
I asked my new job for a standing desk - and I've kept that practice up at every job since. I alternate between standing and sitting on a tall office chair. I estimate that I stand a little more than half the day all in, but being able to transition has made a huge difference for me.
I'm in my forties now and I can grab my feets no problem. I don't do any dedicated stretching - I'm just not hunching all day.