[Voruna] is a skill spam frame, as such, she combines a lot with shield gate setup, and she is really efficient on that, using a decaying dragon key and [Synth Fiber] on your companion, u will hardly die. Honestly, the only mandatory mods are P. [Flow], [Brief Respite] and [Equilibrium], the rest is kinda optional.

Also, keep her 2 passive active at most time, just active the 1 or 3 on controlled situations, like while invisible.

My top recomendations for mods are:

• gladiator set for 330% melee Critical Chance at 12x combo;
• some range to use her 2 as a greater gap closer and improve it's status primer efficiency, but not enough to make gloom (if using it) affect the hole map, as that may generate Kill per Minute issues, because the targets would get stuck far away from Voruna and behind walls;
• 2 augur mods on her + 2 augur mods on pistol to allow her to instantly shield gate with her 1, that said, Brief respite alone allows her to shield gate with her 2, but her 2 needs a target to use.
• strength isn't that necessary, the only thing on her kit that is worth it and scales with strength is her 1 and doesn't need that much, as increasing it may have diminished returns, in comparison to just using gladiator set, also increasing the strength on gloom may, once again, generate KpM issues. But in case u use something as Eclipse or Roar, then swapping gladiator set for strength may be great, yeah.
  -[Rolling Guard] is a great tool to help saving your butt if the game spawn a nullifier right at your feet or if Acolyte Violence shows up

Also Gloom isn't necessary in a shield gate setup, specially because she has invisibility, but gloom will help to keep your pet alive if needed, I use this setup (but with maximized gladiator mods to increase the stats a bit) on SP survival with a [Smeeta Kavat] and I don't have any great problem at keeping the cat alive, only moments it dies is when I die because I made some mistake :V. Also, u don't need too much strength on gloom, because doing so, once again, may generate KpM issues.

In case u want make [Voruna] tank, swap gladiator set for normal [Vitality], [Adaptation] and [Health Conversion] (yes, [Health Conversion], it will give a ton more armor than umbral set)