COMPL!CATED

actually there is , same as pc, but its much more advance .
its adjusting the kernal for voltage and clock speed . or apps like 3C toolbox
 
 

You're probably talking about the Xiaomi Pocofone F1 video Linus did about using LineageOS or whatever on the Poco to get better pictures etc.
 
For taking better pictures, no need to flash a custom ROM, the one that comes on the device is OK, just install the latest Google Camera App (GCAM) for the device.

hard ware is great, top tier performance, average build quality (camera, screen sound etc).
Poor OS (forcing you to connect to their account), just some os yo want to get rid of at once (eg oppo's color os)
also the screen isnt covered by sides, so get a better case 
certainly still the best value phone

https://forum.xda-developers.com/poco-f1/development
here you go , linage is just one common option, many alternatives with nighty updates. but basics are similar to all phones:
root > install recovery > download & flash custom rom > install gapp > enjoy

I have a colleague here at work who uses the phone and I have a few friends who have it. There's no actual reason to switch from it's main OS to something different, they really improved the OS since it got the Android 9 Pie update. Performance-wise, it beats my OnePlus 6 in Antutu (scores over 300.000!) but looses in 3DMark.
The camera is mediocre, but not the hardware part since it takes great pictures with the ported Google Camera (the camera app from pixel phones).