Guys I found something really interesting:
This program claims to be able to spoof even GPU and stuff by modifying window binaries, so if it works canvas and webgl will change too.
I didn't try it though, as installation seems a hell and it is used for spoofing desktop hardware.
In my specific case I am emulating mobile parameters so I won't use it, maybe someone can benefit from this.
Also it relies on virtual machines which is not the most efficient way considering resources.
AGAIN, I DIDN'T TRY IT I AM NOT RECOMMENDING IT, IT'S JUST INTERESTING