One of the best sidearms I've found for tactical backup damage. Splat and Haymaker combine to provide huge crits and damage with a great fire rate. In addition, Tombfinger Rivens are much easier to get since there are a limited number of Kitguns compared to non-kitgun weapons. These Rivens are also very numerous/cheap compared to other Rivens but they are about to change this with the March/2024 release so this is the time to get one if you haven't already. Critical Chance is the top priority and try to pair with Critical Damage, Multishot or Damage. Pax Seeker is very effective with Tombfinger since it's reasonably accurate and will multiply your headshots by up to four other nearby enemies. However you should experiment with other KItgun arcanes since it all depends on playstyle. Tombfinger with pure radiation damage along with a primary configured for pure viral damage is a great combination for Archon hunts but other damage types can make it effective on any enemies even at high Steel Path levels.