I would like to know if it is possible to automatically link mailbox folders with devonthinkpro folders
Only if these mailbox folders are actually folders in the filesystem and contain .eml files. In that case you could index them.
I am talking about automatically synchronizing the reception of an email on one of the oultlook boxes so as not to have to file the files and update them
No, that’s not possible.
Also, indexing email folders in the filesystem is possible, but not suggested as it will lead to a very poor user experience.
the goal is to be able to find everything for the same subject, email, documents, files and conversation