These things are only available via master nightfall, but they are not a guarantee drop.
I already notice that because of that it, is hard to find people on my clan/friend list to join the grind. It doesn’t help that it forces people to use specific weapons and loadouts they don’t like or would normally use (meaning: artefact mods, auto rifles and smg or bow).
So maybe Ascendant Shards should be obtainable via PvP, master NH and gambit prime as well? Or maybe via dismantling the seventh kepris horn exotic in a row? Or maybe a chance to get them from prime engrams? Or make them guarantee drop.
Or maybe sell them with silver via Eververse. Not gonna lie: I would instantly buy them. (Edit: sarcasm)
I know banshee sells them, but his price is ridiculous so that is not really an option.