Bud Light’s downward spiral has accelerated in the wake of the Dylan Mulvaney debacle — and the carnage has begun to spill into Anheuser-Busch’s other mega-buck brands, The Post has learned.

Nationwide retail sales of Bud Light were down 23.4% versus a year ago in the week of April 29 — worse than the 21.4% decline it suffered a week earlier, according to Bump Williams Consulting and NielsenIQ data.

Meanwhile,…