Disable iCloud mail/contacts/etc account but keep calendar only

iPhone 13, iOS 18.3.1

My wife and I keep our joint calendar on her iCloud account, with sub-calendars for "Home", "Doctor", "Travel", etc. So I need access to her iCloud calendar from my phone. We have done this successfully for several years. I don't need or want to see her email, reminders, or contacts ... just the calendar.

After the 18.3 update I noted our calendars weren't syncing any more. So I logged out of her iCloud account on the phone, and re-logged in. When I did that it gave me access to everything ... mail, contacts, reminders, and calendar. I want to not see her email, etc, but there does not seem to be a way to "turn off" those things other than to completely log out of her account .. which means I lose the calendars as well.

See the screenshot below. This simply doesn't work .. there is no "Use on this iPhone" option. The only option is to completely log out of the account ... including mail, reminders, contacts and (of course) calendars.

Anyone have any ideas how to achieve this without having to completely sign out of the iCloud account?