Currently in Dragonflight, there is no way to obtain this consumable unless you use the LFG tool to queue for dungeons or LFR playing a role that’s high in demand (generally tank or healer) thanks to the Call to Arms mechanic.
This means there’s no realistic way for a DPS player to get runes, unless there’s somehow a short supply of them in LFG (which, let’s be honest, basically never happens), or having to spend nearly 2k gold per rune, which is absurd considering they only last for an hour and do not persist through death.
What ends up happening now, is that a lot of geared tanks might just queue for Normal/Heroic dungeons with Call to Arms, and basically full clear those by themselves, possibly ruining the dungeon experience for other leveling players, an issue I’ve seen being brought up multiple times on places like Reddit for instance.
At least in Shadowlands, augment runes could be obtained through the mission tables, so anyone had access to them.
I do wish they could be crafted through professions or at least being obtainable by anyone from open-world content, such as WQs, rares or chests. Another alternative could be to have something similar to the Alchemical Flavor Pocket, an optional reagent that could be added to crafted gear that can make augment runes persist through death.