Technically, according to the Effect Description, it's not able to be destroyed by anything. Maybe Duel Links has a bit of wonky code regarding the monster but in a legitimate situation, I don't see a way of killing it (Outside of overwhelming it)
Floodgate doesn't target, and Lava Golem is a summoning condition, not a targeting effect.
And yes, Chaos Max cannot be destroyed by any effect. However, effects that both do not target and do not destroy, can affect Chaos Max. The aforementioned Floodgate is one example.
Anything that doesnt mentioning "target" wont apply any "target" effect.
Take ryko for example. It can select ( without targeting ) chaos max dragon with its eff even though you cant destroy chaos max by default.
Different outcome will be applied from sazank . You wont be able to select chaos max since sazank mention "target" in the description.
Magician Girl Archetype also works. They have a Trigger Effect that reduces the ATK of a attacking Monster while giving the attacker a new target. And due the fact that the effects are not classified as "Targeting Effects" or "Destruction Effects", they will work without fail.
True, but it can be recovered with White Stone of Ancients, and once we get proper access to this card I don't think Floodgating one of them is gonna matter too much in the grand scheme of things. Right now the skill you need to play it is trash, but once the card comes out properly it'll be a force to be reckoned with.
It cannot only Monster reincarnation And ancients Work so sorry to dissapoint it says on the card text it can be ritual summoned only not special summoned by other ways i tried doing this on a dueling site doesn't work