I use these for my 3d printer for low current needs....such as fans...Buck Converter

I run this fan and DC-DC. Works great and practically silent.

Noctua NF-A4x10 FLX, Premium Quiet Fan, 3-Pin (40x10mm, Brown) https://www.amazon.com/dp/B009NQLT0M/

eBoot Mini MP1584EN DC-DC Buck Converter Adjustable Power Supply Module 24V to 12V 9V 5V 3V (6 Pack) https://www.amazon.com/dp/B01MQGMOKI/

• WLED running on an esp8266 -- specifically the Wemos D1 Mini
  
• To get 5v for the esp8266 I'm using an eBoot Mini Buck Converter ** Note that these buck converters can be very sensitive, I managed to short one with a screwdriver while trying to get the proper voltage tuned.
• The power supply that came with the govee is 12v DC, that power can go directly through to the led strip on the red and black lines (red is power, black is ground). The white line is the data line which we connect to pin D4 on the esp8266. The esp8266 gets power from the buck converter. I've included a wiring diagram below as well as some shots of my test setup (note my test setup used a different buck converter).
  

https://imgur.com/a/5MI3yqd

If you want to directly exchange the stock fans these are what I used: Noctua 40mm 12v fan for the motherboard and exhaust fans. You’ll also need this step down converter because they are 12v fans instead of 24v but they work well and are nice and quiet. I also keep the exhaust fan turned off all the time unless printing with ABS. Even with a noctua fan replacement in there it’s just so loud because its in a huge echo chamber. For the extruder fan I used this 30mm 12v fan and again used the step down board to reduce the voltage to 12v. There’s plenty of extra room in the extruder head to fit it in there and I haven’t had any cooling problems since installing it.