Rant: my dovetails went from gaps you could park a truck in to tight in about 6 months
I stopped trying to cut them by eye and started marking a 1:6 slope with a bevel gauge on every board, and a guy at the lumber yard in Fresno told me to quit rushing the saw. What finally clicked for you, the sawing or the chisel work?
Wait, you were cutting dovetails by eye for who knows how long before switching to a bevel gauge? That sounds absolutely wild to me, I would have given up after the first gap. Marking every single board has to be the move if you want them tight.