>>3411152Hola,
You have identified one of the two lenses that widely available to do this with. The other is a laowa 2.5-5. It has a wider field of view with similar performance. It is also a lot smaller. I have/use the mp-e 65. No really complaints other than it can flare badly at times and I would prefer a higher blade count aperture for bokeh highlights closer to actually round. I would get the lens hood if you do not plan on mounting lights on the front of it.
Get whatever camera gives you a giggle. Unless you've done a lot of photography already you will have plenty of time to grow into whatever you get before getting a better one later.
Another option is tubes/bellows but for field work that can get a little clunky. They also do not seem to perform as well but is a really cheap way to get started.
I do macro frequently and I am friends with etymologists who do field work. Do you have any questions?
https://www.venuslens.net/product/laowa-25mm-f-2-8-2-5-5x-ultra-macro-2/ 