What is your elevation? 210 isn't usual boiling point for sea level. That is 212, so perhaps you think you are mashing at 151, but really closer to 149....which would explain the high attenuation.
To me, the easiest solution is to shrink the recipe size by half a gallon (or just boil for 30mins or a lil longer basically) while using the same ingredients. It will boost your abv, while keeping all your ingredient percentages the same. Plus no need to buy anything else. But that's the...
So I had given up on a small batch of raspberry mead I made years ago. I packed the remaining 6 bottles into a crate with other "experiments" and forgot about them (knowing that age can help). I tried it after a year or so of fermentation and it was hideous so I figured it might be a lost...
If you are going to use an ale yeast, use something more neutral like US-5 or Notty. Also if you partially submerge the bucket in ice water you can keep your fermentation temp around 60 degrees which makes much cleaner taste.
If it were me, I'd mix 3/4 a glass of it with a 1/4 of a commercial light beer to add carbonation to your beer and kill the sweetness/bitterness a bit. Belgians blend all the time. Who knows, maybe it will taste great blended and a whole lot better than down the drain. I did that with a...
I brewed it with equal parts pils, light munich, and vienna with perle @ 60min & just a little big of tettnanger @ 20 mins. Came out really nice. Not sure if I'd say clone, but really tasty!
There is a great thread on this:
https://www.homebrewtalk.com/f14/extremely-low-gravity-beers-anyone-has-experience-brewing-them-213073/
I recommend a good English mild.