If reaching level 80 in the covenant in one char could just let you unluck the 80 renown in that covenant across all your alts would be one way. Maybe through achievement, small quest or item purchased by a vendor.
Immensly buffing the renown you get from all content so it’s done very fast would be another way. I’ve done the renown farms for multiple chars throughout the expansion and I feel done. Definietly something that doesn’t feel relevant anymore but only something holding you back and that would also hold you back from trying new things, other classes and specializations.