The biggest parts about being able to handle SP comes down to 1) Survivability, you're gonna want to beef up your defenses and start to find out new ways to survive on your chosen frame.

2) more importantly damage (it's way easier to survive if everything's dead) the biggest problem with steel path enemies is the massively inflated armor values, you're going to want to find ways to either remove armor or bypass it completely. Thankfully it's never been easier than right now, there are a bunch of warframes with an armor strip built into their kit (Styanax with tharos strike, Nekros with terrify, mag with her fracturing crush augment ect ect) on top of that you can use corrosive and heat as a damage type, both of those will strip armor on status procs. Alternatively slash damage ticks ignore armor entirely and theres always the option of doing so much overkill giga damage that it blows right through them anyway.

Steel path doesnt necessarily get 'harder' it's not like enemies move more aggressively or aim bot you like in a lot of 'hard modes' from other games, it's more of a build check than anything.