If one googles "gas pressure", one will find many seemingly authoritative sites that say things like "Gas pressure is caused by the force exerted by gas molecules colliding with the surfaces of objects" (https://opentextbc.ca/chemistry/chapter/9-1-gas-pressure/), or "When the molecules of a gas bounce off the walls of their container, they exert a force. Gas pressure is defined as the force per unit area produced by the gas." (https://sciencing.com/what-causes-gas-pressure-13710256.html) Or " Gas pressure is caused when gas particles hit the walls of their container." (https://www.bbc.com/bitesize/guides/zc9q7ty/revision/7). If I didn't know anything about gas pressure, and I started trying to use the internet to understand it, I would very quickly conclude that gas pressure is produced by encounters with walls or objects, and when there are no walls and no objects, there is either zero gas pressure, or the concept of gas pressure has no meaning or usefulness.
Of course that is all nonsense, because gas pressure is a very useful concept, and is easily quantified, in situations where all you have is gas-- no walls, no objects. So what justification can be given for claiming that gas pressure is defined by its interaction with objects, or worse, that it is produced by said interaction? I can't see why this language is propagated so widely, it seems clear to me that gas pressure should be regarded as that property of a gas such that when it exhibits a gradient, it produces a force on the gas (in a fluid description of said gas, where we average over many indistinguishable particles). I don't see why we would ever want to define it as a force on an object, or worse, claim it is produced by the interaction with the object-- as so many sources do. Why would anyone want to think of gas pressure as a force on an object, instead of thinking of it as something whose gradient produces a force on the gas itself?
