Try to get some of the Incarnon weapons from Circuit and Zariman, they are pretty much the best guns available right now. With them and any durable frame you should have no problem tackling most Steel Path missions. You definitely want to grab the Laetum from Zariman, it's one of the best Incarnons period, likely only rivaled by the Torid and Furis. Other good grabs are the Lex, Boar, Strun, Ceramic Dagger, Dual Toxocyst and Burston. Also, I don't know if you are aware but the elemental damage meta is no longer Corrosive but Viral/Slash and Viral/Heat. Mod accordingly.
As for an "EZ Steel Path walk in the park" build, you want either Zephyr or Kullervo. Zephyr is functionally immortal if you are paying even a little bit of attention while CCing enemies and providing damage multipliers. Not a fantastic pick for any mission requiring you to move a lot, but she is queen of Survival, Interception, Defense/Mobile Defense and all the other stationary mission types. Bring a weapon with innate enemy punchthrough like the Tenet Arca Plasmor or even the basic Fulmin. Mod for crit and Viral with Hunter Munitions to proc Slash. Cast Tornadoes, suck enemies into them with Airburst and blast away! As for Kullervo, this guy is just plainly insane. You barely need any mods on him to clear Steel Path with absolute ease, all you really need is a heavy attack melee with guaranteed slash procs on heavy attacks. Two-Handed Nikanas, Scythes, Daggers are all great picks. Mod for heavy attack damage and crit. As for Kullervo himself, slap a health mod, a range mod, some efficiency and maybe Hunter Adrenaline if you don't have Zenurik. Power strength entirely optional, go to 200% if you can/feel like it. Press 2 to get overshields, refresh whenever they pop (they give you 0,5sec of gating so you are very safe), cast 4 on chokepoints to clear out trash mobs and build passive combo, press 3 on groups to curse them and then 1. Enjoy the numbers!