In Apple Pay they are sort of static. Not per merchant, but they don’t cycle by default for any reason. I believe there is a button you can press to have the number changed. I think I’ve seen it before but I’ve never used it.
And of course you could always just remove your card and then re-add it. That would give you a new DPAN.
They're not generally considered stable in the payments world. They can get rolled periodically, even outside of card addition and removal.