Something important I learned via the subreddit: your max health is determined by your average item level.
Let me bold that: Your max health is determined by your average item level. (screenshot not mine)
Don’t do what I did and neglect to replace your sidearm for 15 item levels because you never really used it. Oops. After playing about two hours last night and updating my gear to within a level or two of what I can wear, my max health went from 780hp to 2900hp, and I don’t have a single piece of armor granting max health. No wonder why I had been feeling incredibly squishy.
Also, re: Titanium: you can buy it from an NPC at about a 300:1 scrap/titanium ratio. Can’t recall when this NPC shows up, but she’s been tagging along for a bit.