Poles: I’m skeptical about both the balance criticisms and the knee support. I always use poles when running in order to use my arms as much as possible. I find that it helps my hand/foot synchronization for skimo and VK racing.
But I never use them for steep descents. I never saw any benefits from them on descents and, for me, they usually just get in the way.
To reduce impact, I found they had to be ridiculously long or I would have to lean unnaturally forward. I didn’t like either.
Shoes: I wore boots exclusively when I was climbing a lot (and not really training). After doing a lot of aerobic training, I never wear boots unless I need to wear crampons. I use a Sportiva Akasha for almost everything, including easy mountaineering objectives. I’ve come to hate excess foot weight, so if I can get away with trail shoes, I use them.
In some terrain though, trail shoes will be far less secure than boots or rock shoes. It’s your responsibility to decide what is safe for you.
Here’s a thread on different shoe preferences: https://uphillathlete.com/forums/topic/shoe-recommendations/