Shared contacts don鈥檛 show up in birthday calendar

Hello =)

User A shares an addressbook with a group, it includes birthdays. User A can see all birthdays in the birthday calendar that is automatically shown. Users in the group cannot see the shared contact鈥檚 birthdays in their birthday calendar.

What should I do?

Nextcloud 23.0.8, calendar 3.4.2, contacts 4.2.0

related discussions, but none of them helped me:

pretty old: Shared Contacts do not sync in birthday calendar - #6 by Cryx
in the end someone links this pull request Fix: Birthday calendar issue with shared calendars by max65482 路 Pull Request #31859 路 nextcloud/server 路 GitHub which is still not accepted - will this fix the issue?

originally a different problem, later no responses: Birthdays: some show up, some don't?!

too old: Shared Contacts dont't show up in Birthday-Calendar

more context, and I just saw the last comment, have not tried it yet: Birthdays: some show up, some don鈥檛 路 Issue #3914 路 nextcloud/calendar 路 GitHub