I recommend to NOT use anything like that.
I would say they never really were.
Whenever people have some problem with charging not working right or giving them problems or acting up or the car not being able to go into low power sleep mode properly, the first thing people ask is: "Have you been using any third party monitoring apps? Have you removed them? You need to change your password so it blocks them from connecting to the car and interfering with it anymore, so we can see how the car would behave normally."
They cause headaches and problems and unexpected behavior. Some people use them because they are insanely curious and can't stand not seeing all of the data they can possibly have access to. That's why people do it, but they're generally not helpful.
This is maybe the only real useful thing. The built-in charge scheduling is fairly simple, where you can set a start time, and then it will finish charging to the limit you have set. But if you need it to do something very precise, like start at this time, but then force it to stop at a certain time before it has actually finished charging, then yeah, it would need some external thing to force that. But for most people, it's fairly simple, where cheap rates start at X time, and you can just set it to start a couple of minutes after, and there usually isn't anything more needed than that.