Few kilometres, amount of shade, amount of water in the soil, different type of soil, different history (e.g. used to be farmland or used to be forest) can all

Few kilometres, amount of shade, amount of water in the soil, different type of soil, different history (e.g. used to be farmland or used to be forest) can all be reasons for different results. But yes definitely don't cut everything at once, that ruins the habitat. For the rest main problem is usually nitrogen deposition so key is cutting and removing cuttings to compensate for that i.e. remove nitrogen again. And the time at which mowing gets done is pretty crucial as well and requires some experience with the specific terrain as you point out. But there's way to much nuances to all explain here. By far the easiest way to gain knwoledge imo is finding a local nature organization which manages grasslands in your neighbourhood and see what they do/talk to them. I did that a couple of years and it's amazing what I learned from them (though in all honesty the people there are true specialists when it comes grassland and it's fauna specialists, it's also their daytime job, and there's like nothing they do not know - not everybody is that lucky)