Genuinely curious whether you've ruled out the mundane stuff first - temperature changes overnight can cause cabinet doors to pop open if the latch isn't seated properly, and old houses in particular do a lot of "settling" that sounds way more dramatic than it is.
That said, 3am does seem to come up a lot in these reports and I've always wondered if theres something to that or if its just confirmation bias because we're more likely to remember disturbances at an unusual hour.
Have you noticed any pattern? Like does it happen every night or just randomly, and is it always the same cabinet or different ones? I've been looking into poltergeist cases for a while now and the clustering of activity around specific objects or locations does seem to be a recurring thing worth paying attention to. What's the layout of your kitchen like - older property?