Does Apple allow developers to just charge 30% more when users sign up through iOS, and just note in the app that access to the service though iOS costs more?

Seems fair to me, and let’s consumers know where the money is going (to Apple, presumably to pay for ecosystem things like app privacy and security reviews, billing, etc).

If users don’t like it, then the market will do it’s thing right?

It’s unclear to me what types of messaging Apple bans developers from adding though. Like is it ok with Apple for me to build an app available on web for a certain price, but block access via native iOS apps unless the user agrees to a 30% increase to cover the Apple tax?

I think this is what I would want to do if I operated a subscription service available via native app in the app store.