One thing I hate about art advice in general is that it can be misleading because people never give context. The idea that you have to "know the rules to break them" doesn't make sense because it undermines the importance of whatever advice is being given. Art advice shouldn't be "if you don't do this/ if you do this your art is bad" or "doing this is fine because its your artstyle" because both are 2 extremes that make absolutely no sense; advice should be "when you do ___ this happens. If you don't want ___ to happen then you should do this". So I think a lot of art advice is bad simply because of the phrasing like "don't use black to shade"- this can end up giving you flat shadows because there's no hue shift and it mutes the colour which is why it's not recommended when you're using soft shading, but in cell-shading using pure black works quite well IF you're good at lineart. There's plenty of other pieces of advice that just seems too constrictive (this isn't even my least favourite piece of advice I've gotten) so the artist never actually learns WHY which is why making mistakes is important!! The mistake and failure itself is bad, but if you never do things you're bad at you will never be aware of what needs fixing and your comfort zone will be very small.
To expand your knowledge understanding is vital so in short, i hate any advice that shows itself to be a rule instead of "this causes this to happen" because it limits what you can actually learn.