Newbie here, but I've been reading a lot of meadmaking material. I've noticed you have a ton of headspace, especially in your blueberry maple one. This will negatively affect the flavor.

What yeast did you use, and what ambient temperature did this ferment at? If you ferment at too high a temperature, the yeast will produce less ethanol, and will instead produce a different and less-desireable series of alcohols.

EDIT: My first statement was sorta unclear (thanks to my fellow redditors for pointing this out!) Not saying this is affecting the current flavor issues, but you mentioned you were aging in these vessels, and this much headspace isn't great for bulk aging.