You sound like my biological twin (35years, 11.9s, 1.95m high jump, long and slow hikes no problem)…
There is a saying: sprinters are born, runners are made.
So I don’t see a problem to become competitive. When you look into cycling, there is Alejandro Valverde who used to be a sprinter, but developed to be a grand tour winner. So it’s possible but we have to train more.
I realized my personal weakness is totally ME. I worked on that with the Gym ME and saw incredible results.
So, I think you can achieve whatever you want, but it takes more time to “be made” a long distance guy.