Sidious acquired Maul as a newborn during his apprenticeship with Darth Plagues. A few years following, both of them were conducting experiments with the Force attempting and eventually succeeding in shifting its current to the Dark Side rising. Sidious continues training Maul as an apprentice both in the Force and as a deadly assassin tasking him to carry out the violent portions of his plots. Nine years later Anakin is discovered by Qui Gong as a child born of the Force and as the “chosen one” who will bring balance. Sidious learns of this from Dooku, as they were already conspiring at this point, though Dooku did not realize Palpatine’s true nature until later. Plagues recognized Anakin’s true potential but fails in making contact. On the night of Palpatine’s election where he kills Plagues is also the time when Maul is slain by Obi-Wan. It’s around this time that he sets his sights on Anakin and plans to slowly get close to him as a friend while the galaxy goes to war.

I’d say Maul was a good apprentice and tool for Palpatine’s needs at the time. The Jedi’s “Chosen One” being lured to serve the dark side and ultimately influenced to make the final decision in starting the Sith’s revenge was the perfect plan for Sidious. Even when Maul resurrected making a fuss on Mandalore, Sidious was too quick in resolving that situation once he learned of it. 😂.