Ah I see, well a webM is a no go as I want the transparency there, but I guess using a webP as an image sequence, not as animation is what was meant in the related answer.
Quick bonus Q though, I have like 500 frames of an animation in the webP format, totalling 7Mb of files (little over 1Kb each), but once imported in Godot, it generates in the .import folder files that totals around 100 Mb, is there a workaround that? or reason for it?