IMO they are two separate things. Pushbacks are countable in the context of a debate with both parties present. It’s fine to say “I have two pushbacks on this

IMO they are two separate things. Pushbacks are countable in the context of a debate with both parties present. It’s fine to say “I have two pushbacks on this proposal” because those are specific, countable, contained arguments. There’s also the nebulous “pushback”, which is used to describe general resistance to an idea or plan in an uncountable way. “The general’s proposal was met with pushback from the oversight committee”.