I only can agree with the first comment, check the previous thread. 50mm lenses as far as I know get somewhat different results than 100mm, I’m only familiar with 100mm macro, you need to be as close as possible, usually you’ll be not a spying naturalist, but a mountain hanging above your object of interest. So, don’t care much on how close you need to be, zoom is not needed for macro, 70-300 lens will allow you to photograph stuff from afar, like butterflies, but it’s very much not what you want for macro, you need to run from your insect to just focus on it and quality will be lower. (I had the similar-stats lens, but Nikkor one, and it’s more of “I photograph birds, but also sometimes insects when I can”)