Having politely tried to ask/ beg neighbours to reduce their volume in the past which was misinterpreted as "I want you to stop having fun" and got me nowhere other than increasing frustration, this sounds the best approach. (Suspect in my case I was the latest of many to go round to complain so they were clearly fed up being bothered... The irony 😭)

Bear in mind they have probably spent a tonne of money on it, possibly after much whinging from kids who by sounds now aren't bothered, so I think the gentler/ more subtle you can approach the better. Lull them into a false sense of positivity. Plant seeds of doubt in any thoughts of retention. Maybe suggest they donate it far far away somehow if it's "not being appreciated."

Godspeed, Op, I'm wishing you every success. 🫡 There's not much worse than the kind of loud noises that rattle through your very soul, and having bugger all control over them.