Let me know your thoughts if you try!
Not sure your water source, we are on a well with hard water. I add Biz (powder - cheap from Walmart in the US) it contains some of the good stuff they took out of laundry detergents years ago. I also never use liquid, never add in what the box says, and every so often I run a long clean cycle on my washer when it's empty. If you have one, I would run before you make any change in your detergents as it can clean out anything leftover that Blueberry may be reacting to. Look mid-cycle to see what the suds level looks like and if high, run again. Most people use too much 'stuff' when doing laundry and it builds up everywhere. Even if you change,, without a deep clean of stuff, she can still be exposed which could make you think your change isn't effective when she's just getting access to old, leftover 'stuff'.
Have you ever checked out Gussy's Gut? Supposed to be good for addressing sensitivities through better gut health. It's a freeze dried fermented foods product. I believe you already give your puppers fermented foods but this has a wide variety of.
Not sure if you have access to Tide Free & Clear (it is one liquid that is a good one particularly for allergies and sensitivities). Charlie's Soap is another decent product but doesn't do well keeping whites white.