You did all those repairs to your iphone yourself? I imagine that was significantly more technically difficult than repairing a Fairphone, which is made to be _user_ serviceable.
From there I’ve swapped the battery, moved the logic board and home button to a new chassis, taken the camera module out and tried to clean it, had the screen+top chassis off. It’s not for everyone but it’s not technically complex with many specialist tools, it just needs a battery replacement kit, tiny screwdrivers, workspace, and patience.