Maul (formerly Darth, now just Maul) was once a Dark Lord of the Sith, apprenticed to Darth Sidious. He was trained in the ways of the dark side since childhood, many years before Sidious discovered the existence of Anakin Skywalker. As such, it feels reasonable to believe Sidious genuinely intended to train Maul to be his future successor - at least up until Anakin came into the picture - rather than being a mere placeholder like Tyranus was.
Unlike in Legends, the canon Sidious was loyal to the Rule of Two, so there is no reason to believe he would hold back on teaching Maul everything he knew either.
However, after losing his legs and having them replaced with metal ones, he is not much different from Anakin in some ways. Force Lightning was debilitating but not immediately lethal. What sets him apart from Vader, however, is that he had no life support systems to be fried by Lightning - the reason Vader couldn't learn to use it.
So, it comes down to this: did Sidious teach Maul to use Force Lightning at all? If he did, can Maul still use it? It may not kill himself since he's not like Vader but it can still be more of a liability than an asset nonetheless in most cases.