I have tried the iCloud+.
It’s unstable, incomplete. Barely not shitty.
Deliberately sparsely and vaguely documented. Their support employees don’t know the features around custom domain, HideMyEmail etc and refuse to accept anything about it on email and then being typical Apple they simply say no to saying anything on email - hell, there is no email you can contact them.
They tell you “yes, this is the behaviour” on phone. They tell you “there is not documentation for it yet”, they refuse to say this on email. There is no email address you can write to. “No there is no other escalation or contact”. Trust me it’s a nightmare.
You hate Gmail not having human support? You’ll start appreciating Gmail’s no support when you will actually be talking to Apple’s support human being bots who will make you feel like hitting your head against the wall at least 7 times per 10 minutes while maintaining complete corporate composure and plastic professionalism.
If you want to use HideMyEmail it’ll be not on your domain. It’ll be locked to the subdomain (@privaterelay.appleid.com) of a company that’s the biggest walled garden this planet has ever seen and so powerful that it can just delete your account and you can do jackshit about it - yes, they have done it. The typical “find a connected employee at Google” also doesn’t work.
There’s not even catch-all. Max three emails.
Do yourself a favour and a get a real and dedicated mail provider like Mailbox, Fastmail etc because even after being few years older than Gmail iCloud mail is much much much worse.
Besides unless you’re also sunk in the walled garden up until your ears or maybe forehead you won’t be able to use 99.12% of iCloud+ anyway (Or maybe nothing if you stop using fruit company devices. I am not even sure and couldn’t figure out from their documentation and support)
Edit: Wow! Fruit company fans already at their downvoting game! Amazing! Ffs, if possible try to pull the fan part of that brain out of the place where sun never shines? I am also a “user” of Apple device(s), just not a “fan”. But it explains how yesterday there was a sub thread (on payment cut thread) how Apple fans give a pass to Apple for everything shitty and evil like feckless apologist drones.