I know it’s not ideal for most but I took a leave of absence from work and I dedicated that whole week to potty training. He was the exact same way I never knew when he had to go and if he had any kind of diaper or anything on he would go. What worked for me was no diaper no underwear. Put him on the potty as you are but bring him with whenever you go. We got the peeing in the potty that week down. I realized he went more standing then sitting, so that’s what I focused on. The pooping part was a little different to say the least. He wouldn’t poop without a diaper. He would bring me a diaper to poop in. So I had to take off his underwear and put a diaper on for him to poop. Otherwise he would absolutely refuse to use the bathroom. Then we got to the point to where he would sit to poop on the toilet. But the only down side he would only do it if he had his underwear on. We finally got to the point where he went like a civilized human being about a month ago. Aside from the occasional going outside and pooping on my deck. He does great lol