If you feel this is getting in the way of your riding long distances then you need to practise it, as much as you would working on your fitness or whatever.
I’m not much good at riding hands free either so have gone on rides with the specific intention of trying it on quiet flat roads and a little bit at a time, there’s definitely a knack to it, look ahead, use your core, if you can walk and chew gum at the same time you can ride hands free.
Same with taking a bottle out, you should be able to do that at any time, even when descending, it’s really not that hard, honest. Practise that when you feel safe. And reaching into a pocket or frame bag for snacks shouldn’t be such an issue unless you have severe coordination problems elsewhere in your life.
At the risk of sounding condescending none of these things are particularly tricky, it’s just doing them again and again in a safe space (even an empty car park to begin with if necessary) until they become second nature.
The breathing and eating thing, I think you need to find a workaround for that, but if stopping and eating is quicker and less panic ridden than doing it on the move just do that, it’s not a race is it?