You understand the power dynamics here wrong. You pay your ISP for unfiltered and uncensored internet access and your ISP wants to provide this to you. YOU are the ISP's paying customer. The fact that there are 3rd parties like recording industry associations that want to interfere with your and your ISP's private business is a problem for both you and your ISP.
The ISP will do the least legally possible it can to satisfy whatever these external players are coercing them to do. The recording industry does not pay your ISP. On the contrary - they sue them to court and try to force them to implement solutions to censor your internet without any compensation. All these solutions cost the ISP, so if the court is happy that removing the DNS records from the ISP's primary DNS is sufficient, then so be it. The ISP has no incentive to be hostile towards you or implement any more blocks than the absolute minimum they are legally required.
Cloudflare at least is DNS over HTTPS. They'd have to block all traffic to 1.1.1.1 to prevent you using it, they couldn't selectively block pirate bay.
All US Firefox users, some Linux distros, Cloudflare (and maybe other) VPN users have it by default. You can also enable it on Windows 10/11 or Chrome.
Your router doesn't need to support it, one of the complaints from business/school admins or even just people trying to run pihole network wide is that DoH bypasses network level DNS setup
