I've never had an issue with substrates or feeding in the enclosure. You just have to learn your snake's personality.
I have 4 that live up to the ambush predator that they were descended from. They will not eat unless they are peeking from their safe place. Moving to feed them would have been a failure from the start if I even tried, but I don't. They just have comfy snug hides.
Everyone else eats reliably from the habitat and never tries to strike (except for my very defensive girl). Bedding varies from paper to coco fiber to cypress or coconut mulch. All mulch is a smaller chunks not large chunks of bark.
A lot of people tend to mistake defensive bites for food bites. A defensive bite is typically a bit wild and a good tap. An actual food bite is where they will actually grab and wrap you. Even when mine are in "food mode", they're fairly easy to pick up and move if I had to, because I know how each snake personally reacts to different stimulus.
Sure, they'll sometimes come out with a wild swing when they smell rats being warmed up, but again.... It's knowing personality. My defensive girl will be right up front waiting for food so I need to open her tub slow. Too fast and she's like a cartoon snake in a can.
They're able to be comfy before and immediately after feeding. No worries about getting distracted and leaving them locked in a tub in a cold room because one of the warm blooded housemates had an issue. Lol