Bruce sounds typical and and fine on the Live After Death live album, but not better than the previous 2 tours. This is probably the best he could have sounded live at that time. The next tour showed it too, although his voice was fried from the long tour. 1988 is probably better than 1986. But I don't think the dip is that big or noticeable in the mid-80's.
He also sounds good enough and solid on the Maiden England show given the circumstances, some songs sound rough (Wasted Years, Hallowed), but others like Seventh Son are very strong. I like how he sounds on Dortmund 2003, but not Mexico 2019.
He sounded better live in 1990 than on the album (like TFF album). Then he had some good shows in 1992/1993 (and some very uninspired ones), but not better than BTP era.
Peak 80's Bruce was probably POM tour.