The Jedi were hesitant to train Anakin, because he was attached to his mother, he missed her. And the Jedi, being against attachment and being used to start training children at a much younger age, just felt hesitant to train Anakin. That’s it. No further explanation is needed, everything is already explained in The Phantom Menace. Furthermore, the fact that Sidious and Plagueis were involved in Anakin’s creation was confirmed in the Legends novel Darth Plagueis. However, in the novel it is explained that it wasn’t something that they did voluntarily. Rather, the Force created Anakin as an automatic reaction to their unnatural experiments with the midi-chlorians. Basically, the Force was “pissed off” at the Sith because they were manipulating the Force itself, so it created Anakin to stop themm.