bottom and a vegan and still constipated how?

so ive been vegan for 3 years now or maybe 4 i dont remember. Anyway, the vegan diet has a lot of fiber, i really stay away from processed foods, I don't know I saw those fake meat products like vegan sausages and stuff and I never bought them. The thing is even with me eating a lot of fiber, my poo is sometimes like little pebbles and I heard that that means I need more fiber. I also drink a lot of water, one day i think i drank 5 l. But i still feel constipated and just uncomfortable to do anything. I mean i thought about going to a doctor but i feel like I don't have enough info like I don't track what i eat, when i eat it and similar things.

I heard that you can bottom without even douching, is that real? But like you don't starve yourself, you just eat a ton of fiber and I guess drink tea and somehow when you poo its safe to do anything, but i feel like if ur poo goes trough, you still need to wash it out, who wants to taste poo or feel it on their penis. How I noticed I'm constipated is because even when i poo I feel like there is still something left inside. Sorry if I disgusted you. Like maybe my pelvic muscles are weak, maybe I need to do some exercises to improve pooping, is that a thing? Do kegels work?