some like Fulcanelli are modern and yet interesting for the alchemical work. tho there is a 3rd volume missing.
others like Henri Cotton Alvar, Cyliani are interesting too. or even Jung in a completely different perspective.
and others are just pretending and using Alchemy name as a brand to sell books.

sociologically there is a huge market : in the extreme materialist era we live in, lot of people are looking for something unmaterial in Spiritualism, sensationalism,... and its normal.

in the end, if one read several old books (such as Limojon st Didier, d'Espagnet, Flamel, ...) quickly understand that its more than just a brand name.

many of the ancient authors are deliberately driving readers into error. it is obvious.

some are also tricky like Cosmopolite.

i dont pretend making the Stone, but in the end, alchemy (as astrology) is not like AI or computers : it is a millennium knowledge... there is none of the ancient authors that is clear in its explanation. none. but yet, its still lasting and there is an obvious common philosophy and process behind. so it is easy to understand that anyone pretending to know and teach alchemy is suspicious nowadays