You need sage at least for missile hole if you just want a solo build. Because otherwise you’re taking too much fire from ranged mobs solo.
And you got to keep in mind there are a lot of mobs that are also Link immune. And that’s going to give you a lot of trouble as well.
The 2nd suggestion of Pyro2-3/something/Sage is probably the most viable. For just outright melt face solo build.
Because by the time you level the character up to the difficult zones Agni neck will be in the game. And you’ill have the damage to kill high mdef 280+ mobs that are link immune.
Oh and one last disclaimer. Agni is the only elemental neck released right now and it’s Fire spells. But there are Ice and Lightning variations that have been datamined in the code. So it’s possible Pyro will not remain top dog forever. And they aren’t top dog yet till Agni is released on iToS. But it should be in a patch or two.
You may honestly get your dream some point of having viable Ice Damage dealer at some point if you’re patient. And you might not.