How good is Elemental Artillery over the various levels as the primary/only damage dealing tool for a kineticist? (Especially compared to an investigator's damage)

I'm making a kineticist (with additional unrelated stuff for non-power purposes), and because of unoptimal attribute distribution (0 str, 1 dex, 2 con at level 1, increasing dex+con over the levels) I think my defense and offense will be very low. (Yes, please do write "this is bad", "change your attributes", and similar comments, it increases the post's engagement.) For this reason I really like the idea of this 120 feet range artillery cannon, which I can just plop down to stay very far away from danger but still participate in the fight with damage, beyond non-DC/attack roll dependent impulses (both utility and damage).

To lighten the action load of the artillery, I know I can employ a familiar with manual dexterity to help with reloading. If I give it independent too, it can also help reloading by itself. Because one can't summon the artillery in an occupied space, and a tiny familiar has no reach, it has to spend an action to enter the space of the artillery first be able to start reloading. Unfortunately because the kineticist's Elemental Familiar feat locks down one familiar ability, I will have to gain the familiar from other sources, probably adopted ancestry into gnome, kholo, or ratfolk.
Also from level 12, Effortless Impulse can help with it's free sustain.

It's unclear to me if I can sustain the artillery more than once per turn, being able to reload/fire it from afar (like me sitting behind cover, and the artillery being in the open), or I can sustain it only once per turn and for further reloading/firing in the same turn I have to be adjacent to it and do it in the manipulate action way. I know I can't sustain a spell multiple times in a turn for the purposes of it lasting longer, but I don't know if it forbids me to sustain a spell multiple times in a turn at all.
Relevant rules text:

Sustaining more than once in the same turn doesn't extend the duration to subsequent turns.

I think my other options for contributing in a fight are non-DC/attack roll dependent impulses for buffs, utility, and some of them for damage too, or relying on the investigator half of my dual class PC to do damage. How well does elemental artillery compares to a (maxed out int) investigator's output?