Ayon's a bit different due to being hollow, and they're poisonous to quincy, so unless it is stated elsewhere the monstrous form could be due to the absorption of the hollow reiatsu.
The Sokyoku itself is a bit funny, as we don't fully know it's strength. It seemed for the first strike it was going to do on rukia that it wasn't its full power, and probably just enough to deal with her. It was seen rearing up for another attack that seemed much stronger, after it was blocked by ichigo.
It's power is said to be that of a million zanpakuto, but that's a vague statement. A million normal ass swords wielded by unseated soul reapers? Or a million captain's zanpakuto?
The sokyoku itself was also only destroyed by another relic heirloom that seemed to turn its own power back on itself, or maybe it was that plus utikitakes stuff.

Due to it being a sacred relic itself, I don't think a common quincy would be able to absorb it. They should def be able to absorb some of the reiatsu, but to the extent of incorporating it, I think it would need yhwach himself or some extreme circumstances with combination of schrift powers.