That is good to know and very nicely conveyed, it makes sense. Even the "macro" lens I have now (which is probably like you say a close up lens) gets really dark and I think the lowest F stop it has is 5.6 and even that is darker than I would like in normal sunlit conditions.
It would definitely need a lot of practice to get used to a manual focus lens that doesn't have an adjusting ring. I will keep a lookout for one in the classifieds as I'm quite intrigued by it and the photos you can capture with it.
no idea what camera you use but you could have a look at their website , this is the lens i use
https://www.venuslens.net/product/laowa-25mm-f-2-8-2-5-5x-ultra-macro-2/
but they make many other macro lenses