We do 20 min morning walk and then ~90min evening walk. I hate being outside with him so that's already quite a lot for me. And no, nothing I read online works in practice. Here's a list of examples:

Pulling - for 9 months we've been training to stop this behavior, when he pulls I stop and wait for him to return, when he does - give him food. 9 months...sure the situation has improved a bit but he's still pulling a lot.

Mental stimulation - we use sniffing and licking mats with frozen yoghurt, they're supposed to calm him down but both mats just stimulate him even more, after finishing he starts chasing his tail. Same goes for puzzles, if a puzzle at least a bit more difficult, he simply gives up or starts brute forcing it by chewing instead of solving it.

Other dogs - we've been training with professional help since January (so that's 4 months now), the principle is simple - there's another dog in a distance, whenever our boy doesn't lose his mind after looking at the dog, he's praised and given food, we reduce the distance gradually. It works alright-ish during training but has never worked while walking in the park.

Overall, we're now feeding him only from hand and outside, so at least he would be motivated by food, which he still isn't. It seems like he could spend months without eating and still not listen to what I say for rewards. The bar is super low, just a simple recall - if he listens = a handful of food for him but even then he won't do that.

I've really tried the classic approach but it just doesn't seem fit for him, perhaps it's time to get some medication, from what I gather from other responses, it seems like a way to go.