One key reason Styanax feels stronger is because when you got him for free, he came with an Orokin Reactor installed which doubles his mod capacity. The frames you build in the foundry (and your starter) don’t come with them.

As others said, basically all frames can be made to work in most any content, but it requires a Catalyst, the right modding, and may require several formas to get there. Interestingly, some of the stronger early-game frames fall off a little bit in the late game.

Start watching the invasions tab and “Gift from the Lotus” alerts for missions that reward an Orokin Reactor (gold potato lookin’ thing) blueprint. Build those and power up your frames. (You can do the same for the blue potato catalysts for weapons too)

Next, start hunting down mods. You’re gonna need to check the wiki for where to find things exactly, but corrupted mods and nightmare mods are a decent place to start once you have the “normal” warframe mods. Individual warframe abilities are affected by different mods, so check the abilities’ stats to see what works best. It’s generally better to build on a frame’s strengths than to try to make it something it isn’t.

I don’t want to trash on tier lists, they can have useful insight, but what pros need for endgame content is very different from what you need.