Am I playing the game wrong?

Hi everyone, so, I've been playing the game for two weeks now and I feel like I'm just not playing the game right.

I'm really enjoying the game, but I am now MR6 and in Saturn, but I'm stuck on surviving 30 minutes on Titan. I've tried like 3 times and I'm not even close to achieving it, I feel the enemies are getting way too strong and I just don't know what to do. My damage isn't enough, so I joined a friend's clan, but nobody is active anymore in there and they haven't researched anything, so I can't really build things from there.

And, speaking of that, I've been able to get all but one part of the Sevagoth Prime, but it turns out the last part not only is really hard to get, but it's about to be vaulted? I don't know, it feels like I'm always one step behind and it's getting frustrating.

The last few bosses I've defeated had been so counterintuitive and it's fine to not be held by the hand, but it takes me like half an hour to defeat them, so I can build a new Warframe, because I already have all of mine at lvl 30, so I'm not really leveling that much anymore, so it feels like I just hit a wall and I'm stuck in a loop that's getting me nowhere.

So, idk, any advice? What am I doing wrong? I love this game, but it's getting frustrating to see everyone else being better at it.