@MattKB Presuming this is you, here's some feedback! (and presuming it's working properly, I'm not sure I trust it since some data is missing!)
Oh my goodness mate, your heroes are very low level!! By the time my second account was at SSD5 in Stonewood, my 4 mains were all at least level 10, some of them even evolved to 2* and level 15. Levelling heroes will give you more survivability in missions, make you deal more damage and get you other perks.
Your FORT stats look ok, and similar to what mine were at that stage, but it seems like you could do with spending points on your survivors if possible, they're basically all lvl1.
I also had two more survivor slots unlocked - this makes me think you've been focusing on getting the stat upgrades in the skill tree initially - totally understandable since you said above you've found it confusing, but spend your next points on the survivor squad slots (or just wait for the update, lol!)
Also worth noting the priority for squads to use where possible is: Leaders always match the team if possible (this will double their contribution to your stats); if you can't match the team then use the highest rarity possible. Regular survivors need to match leader personality where possible (they get a small bonus to their value depending on leader rarity), otherwise use highest rarity possible. Try not to spend points on blue / green / grey survivors, focus on purples/oranges.
It also looks like you haven't levelled any schematics up, bar a single assault rifle which is at lvl 2. You need to upgrade them to at least level 5 to start unlocking their extra perks / abilities. Traps desperately need levelling to keep up with the husks getting stronger. For reference, my traps and weapon schematics were between level 5 and 10 at SSD5
In short, no wonder you're finding it tough!