Sounds a bit like what I went through with my Irish red batch. I used the Nottingham ale yeast and could not get the fg below 1.020. Even added another packet, but I should have added a different yeast instead of another Nottingham. I was going to bottle it to give to a neighbor but I kegged it and kept it as I was nervous it wouldn't taste good. Made another batch with non English yeast and it finished where it was supposed to so I bottled that batch for my neighbor.
But after carbonating the first batch in the keg....it tastes fine to me and it's my " session " Irish ale. Still drinking it now.
Try the advice to add a different yeast and see if it will finish. But I bet regardless, you will have very drinkable beer so don't dump it.