Hey,
to be honest there isnt really a real rotation because you have lots of situational skills on your hammer.
Example: earth 4 gives barrier on block and water 4 heals your by a big amount so if you need hp at that time, you are going to swap to earth or water for the barrier/heal.
However if everything goes right and u dont need any hp, the rotation is somewhat:
Jump with jackal in the fight for barrier.
Start with full or half energy in earth attunement.
Hammer 3 -> Signet of Fire -> signet of Earth -> hammer 2 -> During the casting of hammer 2, place earth sphere (combo field) -> hammer 5 (combo finisher).
Swap to Air.
Hammer 3 -> place air sphere (combo field) and instantly use hammer 5 (combo finisher) -> hammer 2.
Swap to Fire.
Hammer 3 -> place fire sphere (combo field) -> hammer 2, hammer 5 (Combo finisher, doesnt matter if hammer 2 or 5 first) -> hammer 4.
Swap to Water.
Hammer 3 -> Summon Ice Elemental -> hammer 2, hammer 5 (Combo finisher (tho you dont have a combo field at this part) again doesnt matter which one you use first) -> hammer 4 (combo finisher) (if you need 4k hp).
Auto attack until you have like 29-30 energy.
Swap to Earth.
place earth sphere (combo field).
hammer 3 (grand finale (combo finisher)).
Hammer 3 -> ....(same as above)
My videos can be different from the rotation because I was in need of hp or somewhat like that.
Signet or fire and signet of earth you can spam instantly after CD tbh.
Small important note for Signet of Earth:
There has to be a 3 second time gate between Earth hammer 5 and Signet of Earth (what I ironically failed on balth solo).
This is because of the trait Strength_of_Stone which causes bleeding on immob but with an ICD of 3 seconds.
Its a small dps loss if you cast them both at the same time but its not that important.
Other stuff you need to know:
If you know there is an invulnerability phase incoming for the boss, keep in mind that you will lose your orbs because of a bug (I hope) that orbs currently have.
This can kill your rota basically.
If you are in need of hp, dont be afraid to summon your ice elemental (so swapping to water) instead of the listed rotation. Its ofc a dps loss but in open world solo its sustain over damage.
Remember to read the skills to know what are your combo finishers and always use your combo finishers in your sphere.
combos give auras and auras give elemental empowerment. So combos are a source of both sustain and damage.
There can be cooldown issues sometimes and if the skills are still on a too big cooldown, just skip the skill and swap attunement.
If its just 1-3 seconds, you can wait in the attunement to cast it.
If the boss is low hp (around 5-10%) and the next attunement would be water, but you also have air, fire or earth ready, you can go on earth, fire or air to finish it off, since water is the worst damage attunement on hammer (also also on most other ele weapons).
If the boss isnt low, you shouldnt skip water because water is a good source of healing (hammer 4), condi cleanse (hammer 5), combo finishers (hammer 4 and hammer 5) and soft ccs (chill). It also causes vulnerability with its orb.
The utility skill for blocking attacks (Fortified_Earth) :
Dont use this instantly after you applied a jade sphere, because this utility skill has a 3 second duration and will ruin your combo.
Example:
apply fire sphere -> fire hammer 2 -> fire hammer 5 -> Fortified Earth. ||| Good!
apply fire sphere -> fire hammer 2 -> Fortified Earth -> fire hammer 5 ||| Not Good!
This is because the fire field will then already disappear before you can blast the combo with hammer 5.
Other notes about Fortified Earth:
Dont dodge while using it, otherwise you will lose your 3k barrier. Because as the description says, you only get the barrier if the channel completes successfully.
Other notes about combos:
As you can see in the rotation, the is max. 1 skill between the jade sphere and combo finishers.
Casting a leap or blast finisher in the water field of water sphere will give you healing.
So its also not too bad if you skip fire sphere to use the water sphere if you face harder bosses.
Why the Fire sphere?
Its the least important one. Earth sphere gives protection so thats obv important and air sphere gives quickness for a smooth rotation.
Fire sphere basically just gives a dps increase due to might.
For the elite skill:
You can also already cast it before the fight if you dont have jackal.
Dont spam it: If you use it while full hp the healing will obv be fully useless so only use it if you have around 5-8k hp already lost.
And remember that it has a cast time (the elemental first has to cast it (sometimes very slow)) so dont use it in the very last second, otherwise you will be dead.
I think thats all you need to know.
I know its a lot...so yeah...as I said, its mostly very situational xD
However I would say you can use the above listed rotation as the base thing and if you need anything of the other attunements, just swap to them and dont be afraid of killing your rotation.
At the end you just swap between attunements depending on what you currently need basically. xD