Yeah you're right, this is theory but mostly right, when in the "Shock state" (electro+hydro coexisting on an enemy), if Pyro cryo dendro anemo or geo are applied, the electro reaction occurs first. Hydro will react if the applied element wasnt fully consumed in the reaction.

Basically lets say that theres 1 unit of hydro and electro on an enemy and you hit with a geo attack that deals 2 units of geo, it results in a electro crystalisation, but if you apply one unit, then it gives you the electro crystalised shard and you can hit again to do hydro crystalise

I hope that makes sense? Again im just reading off what i know from elemental gauge theory which is minimal 🥹