The Rule of Two being a thing to hoard the Force kind of breaks when think about how Sidious and Vader trained multiple people. Bane didnt think the Sith were spreading the Force thin, he believed jn consolidating the knowledge and ability of the Sith.
For instance, in high school you learned from several teachers because all of them were only proficent in one subject. But what if you had one teacher who was able to master all ths subjects and you only graduated if you knew everything that teacher knew. And sense that teacher no longer knows more than everyone else, youre now the teacher. So each new teacher knows more than the previous. With the Sith each one had to be stronger than the previous on or the order died.
Im not sure if Darth Plagueis being alive during TPM is canon anymore. I also think he knew Maul was alive but didnt care. By then Dooku was more useful and he knew about Anakin.