Ok @eagleeye, thank you for your patience! After the webinar I did some research and have come up with the following conclusions that I hope will help you land on which macro lens will best fit your needs.
First, as @dfrazer mentioned, what makes a macro lens a macro lens is that it can focus on a subject 1:1 at it’s minimum focus distance. But the space needed between you and the subject changes based on the focal length of the lens. With a 35mm macro lens, you have a working distance (the space between the front of the lens and the subject) of less than 2cm! However, a focal length of 100mm is going to give you a working distance of more like 15cm. Both will create a 1:1 photo of your subject, but the longer the focal length, the more space you have to work with between you and the subject. This is why I think the popular macro focal length range is between 60-100mm. There’s more space to work with skittish critters or various lighting setups. (More on this first point here: https://digital-photography-school.com/working-different-focal-lengths-macro-photography/)
However, you should keep in mind that field of view with a macro lens works exactly the same as any other lens. The wider your lens, the more background you’re going to see. The more telephoto the lens, the less background you’re going to see. So, with something like the Laowa 15mm macro lens, you’re going to be able to get epic landscape photos with tiny foreground objects appearing ginormous. Of course, you’ll have an extremely tight working distance, but you’re going to get out of the ordinary perspectives. On the other hand, a regular 100mm macro lens will render backgrounds more like what you’re used to seeing in macro photography. (More about that in this extremely helpful video: https://www.youtube.com/watch?v=aJXDVDXvD44)
Something else to think about is “multi-purpose”. You don’t have to use a macro lens just for macro photos. They work like any other lens. So, if you’re looking for a good portrait lens, then perhaps you could kill two birds with one stone by getting a macro lens in the 80-150mm range. Now, keep in mind that true 1:1 macro lenses (as far as I know) are only prime. If there’s even such a thing as a zoom macro lens, then it would probably be very expensive. But of course, there are zoom lenses that could provide a magnification ratio that’s good enough. Like 1:2 or 1:4. But that would only be if multi-purpose is high on your priority list.
So, having said that, I think any other considerations would simply be what you would consider for any other lens! Like sharpness, distortion, bokeh, brand, build quality, etc.
For a head-to-head comparison on 6 affordable macro lenses, you take a look at this excellent article: https://photographylife.com/the-best-macro-lenses-for-nikon
And let me know if you have any follow up questions! Would love to hear what you decide on getting.