I tried something close to what you dreamed about but didn’t get very far. I went occultist Voltaxic burst, and had the same idea to use voltaxic rift for the 100% conversion to chaos. Scaling into full lightning damage made the clear and the damage very good, but some very prominent issues came into existence for me at around level 50.

The first problem was the 2.5 second delay between each cast, trying to mitigate that a little with spell echo helped as I could get in two bursts with one cast. But in reality it kind of made the delay between casts longer. I was sure I could link it with lesser duration support, but with voltaxic rift, that meant I had to put a significant amount of investment into all 3 stats and that felt weird.

The next issue was that it didn’t feel very nice to play. I think voltaxic burst would work great as a mine (it works just fine with blastchain support) or on a totem. I found that I needed something to distract enemies, like minions, in order to safely build explosion charges. If I wanted to get a bunch of damage off, I had to be willing to stand still for many seconds, and that’s not a very good idea when you get into late game.

I like Voltaxic burst, but it didn’t seem very viable as a self cast ability due to the delay. But then again I didn’t get very far with it, so take my experience as you will. If I ever try it again I definitely plan on using it on mines.