You can still block access by host by using an HTTP proxy like Fiddler or Charles.
Settings > WIFI > Proxy
I use adblockios and haven't upgraded because they unblocked the blocking. I keep hearing about charles, I wonder if it is special or if it doesn't really block everything.
... and that apple wants to merge its operating systems
No they don’t. They keep adding new ones.
They want to provide a consistent user experience across their ecosystem. Not the same thing.
Unfortunately the consistency is moving in the direction of iOS rather than macOS.