You have a mixture of fans there, and that poses at least one problem. The case came with 3 fans from DeepCool, plus you have one SP120 RGB PRO from Corsair. You have not told us which model number of DeepCool fans you got. If you cannot find that on them, tell us three things about their connectors and labels:
(a) for the MOTOR connector, does it have three holes or four?
(b) for the LIGHTING connector, does it have four holes in a line, or three holes that look like it was four, but one is blocked off?
(c) what does the label on it say about the Amps or Watts the motor uses?
Next, if you look at the one Corsair fan, I bet its LIGHTING connector has four holes BUT it looks quite different from those on the DeepCool fans. That fan is intended to be used with another Corsair Accessory, their Lighting Node Core unit. For your purposes, it would be easier to get a different fan with "standard" cables. IF you do that, you should look for a fan with these two characteristics:
(a) the MOTOR connector should have the same number of holes as your DeepCool fans do.
(b) similarly, the LIGHTING cable connector should have the same configuration as your DeepCool fans do.
I have to presume that the case and fans from DeepCool included some means of powering and controlling their LIGHTS, perhaps through a lighting hub with a control button on the front. Assuming that Hub has only three output ports for the case fans supplied, we'd need to find a lighting Splitter that fits there to add a fourth fan's lights.
For power and speed control of the case fans, there are good ways to connect three or four of those to your single mobo SYS_FAN header. Details depend on what you tell us about those DeepCool fans.
For the CoolerMaster ML240 RGB AIO cooling system, you can do it all from the CPU_FAN header using a Splitter, although the instructions for that system show you using two mobo headers. To do that you will need a 4-pin fan SPLITTER with at least three outputs. Examples
https://www.amazon.com/Splitter-Com...1&keywords=fan+splitter&qid=1614136164&sr=8-4
That has three output "arms". Of those three, if you look closely at those arms, only one has all four pins, and the others are missing Pin #3. It may not seem right, but you use this by plugging into that one 4-pin output the cable from the AIO system PUMP unit that has only THREE holes. Then both rad fans plug into the other two arms. The Splitter input connector plugs into the mobo CPU_FAN header. In BIOS Setup see your mobo manual p. 2-3 for Advanced Mode, and choose the F6 key to get to QFan settings. Look for an option to choose PWM Mode or Voltage Control Mode (aka DC Mode), or Auto. Set this to PWM Mode, then go though the Exit Menu to Save and Exit. When you do this, the PUMP which is wired just like an older 3-pin fan will receive a constant 12 VDC power supply and always run full speed as it is designed to do. Further, its SPEED signal will be monitored by the header for pump FAILURE; if that ever happens, you will be warned immediately and the system MAY take its own actions to shut down and prevent overheating damage to the CPU. The rad fans will receive that same power, but also will receive the PWM signals they need to control their speeds automatically according to the CPU chip's internal temperature sensor. Note that, in BIOS Setup, it will show you the PUMP speed with the label CPU Fan Speed, and it can NOT show you the speeds of the rad fans at all.
Here's an example of a different design of Splitter that looks like a circuit board
https://www.amazon.com/Endlesss-Spl...1&keywords=fan+splitter&qid=1614136805&sr=8-5
If you get one of these, plug the PUMP into the output marked "CPU" - that's the only one that can send back to the header the pump speed - and plug the rad fans into other ports.
the combined power requirements of the pump and rad fans can be met from the single CPU_FAN header. Power and control of the case fans we can settle when you have told us exactly what case fans you have, as above.