For me personally, I wasn't able to completely get rid of off flavors until I had full fermentation temp control. Not sure if this is what's causing your problem, but it sounds similar to what I dealt with. Always the same weird flavor & the beer was drinkable but not good
The other night, I opened up an oatmeal stout I made about a year ago. Must have over-carbed it or bottled too early because about 1.5 seconds after there was a volcanic eruption of oatmeal stout in my kitchen & in my face...
Anything I've made has gotten better with age. Also, I would think a bigger beer would benefit more from aging. Gives the flavors a chance to mellow out and all that good stuff.
I just started out earlier this year. Obviously didn't do enough research because I ended up with a plasticky-banana scented/flavored nightmare :ban:. It was enough for me to never let that happen again. If there's one thing that will make you pay attention to temp control its dumping out 2...