Mostly for my clan...

Not really an original build since I'm pretty sure everyone is running something along these lines with mostly minor changes except for Heavy Caliber replacing Vile Acceleration being the sole major change.
This is mostly due to the Viral/Slash meta as you probably guessed.

You add in the standard damage template ([Serration], [Vital Sense], [Point Strike], [Split Chamber]). Then slap Viral on through a combination of Primed Cryo Rounds, Infected Clip, Rime Rounds, or Malignant Force depending on the weapon fire-rate/type, magazine size, and innate status chance. Then add in [Hunter Munitions]. On rarer occasions with weapons that have innate elemental damage, you could even add in Fire.

Personally, I left out [Infected Clip] and [Hunter Munitions] since I did not feel like I needed the extra damage and spread for the content that I would normally use this gun in. Obviously, switching in Infected Clip and Heavy Caliber gives you higher DPS on all fronts, but I don't need that damage and the higher fire-rate allows me to spam more enemies. In Steel Path, I would just use my melee weapon anyway.

If you really want [Infected Clip], add in another Madurai Polarity (V) and replace Malignant Force with Infected Clip.

If you wanted to use Heavy Caliber and you screwed up like me forma-ed your [Trumna] this way, you have two choices. You can get rid of [Stabilizer] or you can you can keep it with more forma. If you are deadset at keeping [Stabilizer], you might as well max out your forma at this point since you'll need two formas anyway. Add in two more Madurai Polarities (V). Take out Vile Acceleration and Malignant Force. Replace them with Heavy Caliber and Infected Clip.

https://imgur.com/a/u5N7pTd