how far the low pass filter can go

This is how far the low pass filter can go when you eq any instrument in fl studio.
And low pass filters are needed when you want to remove the presence and treble of instruments to make space for another instrument to cut through.
This frequency cutoff is recommended for complete beginners but if you intend to go lower than what you see in the Rumble video then you are not doing mixing.
This is what adcanced and professional mixing engineers do behind the scenes.
I know that other YouTube mixing engineers will show you how to add low pass filters in equalization otherwise than what Young Amo Music showed you.
low pass filter audio can not be ignored at all.