pls dont fix my strats :]
but if you REALLY want to all you'd have to do is get rid of all non-orthogonal clip brushes. from my experience almost any brush that is rotated an angle of not a multiple of 90 degrees can be wallbugged on. snake seems to have the most abuse-able ones out of the 6s maps (back of yard, above bridge on second, above catwalk on mid, above saw on mid, top right and top left at last off of the top of my head). clip brushes should be easy to deal with, as for actual walls that are angled in the map, i'm not sure how you'd fix this other than redesigning portions of the map itself (but then again the only actual angled wall that can be abused is top left at last if i remember correctly)
EDIT: possible wallbug fix below (IGNORE IT IS VERY INCONSISTENT):
disclaimer: im not super knowledgeable about mapping or how the engine works so feel free to tell me why this is a bad idea
it seems like any brush that is tied to a func_brush entity resists wallbugs. i dont necessarily know what func_brush is intended for, but it looks like, for all intents and purposes (and with the default settings), it functions as a wall. what's even better is that if you tie a clip brush to the func_brush entity, it seems to resist wallbugs as well. i made a little video to show what i mean:
if ur a source/hammer/jumping god lmk what u think. i feel like all of the oddly-angled walls and clip brushes in every sixes map can be fixed this way.