I'm having troubles and need help

So my build is doing tier 12ish maps BUT I feel like I am struggling to get through them. How do other SR/RF builds make it so seemless? I keep dying faster than I can level at this point because I feel like random mechanics kill me (Syndicate trying to assassinate you anyone?). If anyone can give me some feedback on how I can sustain bosses better and also anything else I can have to enhance my build? (Also I plan to get a Kaoms heart once I can afford it and then 4l Scorching Ray in my boots)