The problem is that if you consider Discovery non-canon then it has to follow that Strange New Worlds (which spun off from Discovery) is also non-canon and that would be a shame. It (and Lower Decks) are the only new Trek shows that feel like they actually truly understand Star Trek.
according to what i think i read here, Lower Decks revealed that Discovery was on another timeline, so in that sense it would remain canon (for that timeline) and just would not effect the prime timeline
