@Rodolfo2909,
The purple streaks are due to a Memory Test that MacOS performs on AMD GPU's during the boot phase.
Due to the differences between PC's and Macs memory mapping, the test overflows from the VRAM to the Display Memory which is what causes the Purple lines.
WhatEverGreen disables the memory test thus avoiding the purple streaks ....
In most instances it is purely a cosmetic issue, however if you boot in verbose mode then as the screen updates it overwrites the purple lines causing the memory test to fail as the read back values miss-match ...
Cheers
Jay