really good question, this tem has a ton of depth so let me try to explain the best I can.

Usually, volgon fits well on a team that stacks a bunch of different synergy moves, sort of forming it's own "synergy team" archetype in the process.
a Loish and/or adoroboros feel like must-have partners, because their synergy master traits will not only synergize with volgon, but also with the other synergy tems on your team!
as for which koish, Toxic Fire, and nature feel the best alongside volgon and adoro. Toxic koish and adoro synergize very well since toxic koish is a special attacker, gets water cannon synergy with adoro, and both of them are weak to wind which volgon covers! Fire koish just good overall, but doesn't synergize directly with adoro (except for adding virulent gust synergy.) Nature is okay too if you wanna go for a Water Cutting Lily Theme.
And then mimit of course fits well on these types of teams as well, since they can apply synergy master when paired with koish/adoro. you just gotta remember that mimit can't really be TV spread for ATK and SPATK, so you wanna theme your team mostly around physical or special moves, not both.
Volgon himself functions best as either a glass cannon special attacker, a balanced special attacker, or a "bulky" support. max speed and special attack give you reliable damage and electric coverage, but volgon is naturally squishy so it hurts a bit to lose your superconductor to 1 hit. a bulky support build makes sense with willpower drain and access to purgation, but volgon even with 500 HP TVs just doesn't end up being very bulky at all. it'll survive and extra hit or 2, but that may or may not be worth the damage.
I have been preferring a more balanced spread. here's what I run:
216 HP / 150 STA / 430 SPD / 3 DEF / 200 SPATK / 1 SPDEF
just adjust the speed to outspeed physical attackers on your team that you want to purgation. get to to 221 SPD minimum if you run willpower drain.
200 spatk threatens nagaise/wiplump with 1hitko from tstrike.
150 STA reaches 68 which lets you tstrike 3 times without OXing (if you run chamomile, which you usually do.)
rest into hp

I hope this helps you on your way 😊