I've never had an erection myself, but I've handled a few. My husband is twice the OP's age and he's probably a 70% too. But that's good by me, because his I can accommodate him much better than when fully erect. I would say that over half the time he rarely gets fully hard, but when he does it does become difficult for me. I'm not small by any means, but he's definitely not small. Sometimes I can stimulate him to a full erection, but that's usually just for oral. And sometimes he does become more erect during penetration. That's nice, too.
He did try ED meds and if there's such a thing as too erect, like 125% erection he got it. Not a good thing for me at all. He loved it, of course, felt like he was swinging a baseball bat. I didn't mean to laugh, but I never saw it point up before. Like a little kid with a new toy.
So, Sweetie, if you won't go to the doctor then find yourself a friend who might get you past the 70% or who likes the 70%. Might be a whole new experience for you.