Our party consists of the following:If you have a martial that stays at range, that just means the monsters are that much more likely to target you instead.
And it's a natural instinct for many GMs to play the monsters "smart" which in this case means "avoiding the hard target", the Champion.
If so, your party might be imbalanced in the area of sharing incoming damage.
I strongly believe every martial must take on the very essential task of: soaking (or negating*) damage.
*) it's almost impossible to build a character that doesn't take damage. The monsters are simply too dangerous.
If the fourth character is a squishie I can definitely understand your pain - not only do you compare your defense with the best defender of the game, you don't get much help in the most important task either: causing damage. After all, when all monsters are dead, you don't need a high AC...
Champions and ranged fighters have both considerably lower DPS than you do. Your allies need to, at a minimum, realize it is in their interest to keep you standing to output your impressive DPS even though it means inconveniencing themselves.
In contrast, the five-man party I'm GMing feature one barbarian, one fighter, one ranger - all melee warriors. The barbarian might take a bit more damage than the other two, but is also doing huge amounts of damage herself. If she's at risk of going down, she can rely on two allies to step up.
And of course, the impressive healing power of the Cleric. (Only the fifth character, a Wizard, feels like it is playing in junior league)
My suggestion would be to have the archer character understand the necessity to stay close to enemies and divert some of the damage you're currently soaking onto his or her own body.
After all, in a game with "free" healing, taking damage is not a problem. Only taking too much damage in too short time is.
Bottom line is: it might not be entirely your fault your character is taking so much damage...!
1. Dragon Instinct Barbarian
2. Gymnast Swashbuckler
3. Storm Druid
4. Lesson of Fate Witch
I thought the barbarian would be more tanky with higher hit points, but he seems to be more like a rogue using rage for big damage instead of sneak attack. He really takes a beating. The Swashbuckler takes a beating as well. The class doing the best is the druid who can do a lot of things. She combines electric arc with her bow, sometimes has the animal companion attack, heals, and casts her focus spell dealing a lot of aggregate damage and heals damage. Witch adds damage with cantrips and boosts with nudge fate.
We're running The Show Must Go On. A lot of tough encounters in that module early on. I noted the difference with our other party. Barbarian seems to be taking damage more like a rogue than a champion or a fighter.