I have been using Samsung Calendar for a couple of years on my Samsung Galaxy S21 FE. I use it to sync 4 different calendars (3 from Google, 1 from Outlook).
Some time ago, for each of my Google Accounts, there were two separate calendars: one for "normal events" (my_email>@gmail.com) and one for "birthdays" (Birthdays) of that account (NOTE: this is NOT the "Birthdays" calendar for Contacs on the device, but the one from the Google account). This was very useful because:
I could set two different colors, one for non-birthday events and one for birthdays
I could turn them on/off indipendently: meaning I could turn off birthdays to have a quick glance of my upcoming events (I have lots of birthdays so the calendar view is a bit "noisy" with them always on.
However, after a recent update, for each of my Google Account I have a single <my_email>@gmail.com calendar which has both the events and the birthdays: they are indistinguishable from each other having the same color, and I cannot turn the birthdays off without also turning off the normal events. It seems that the 2 calendars are merged into a single one.
This is not a minor inconvenience, it makes Samsung Calendar almost unusable for me, given that on my Google Account I have lots of Contacts with birthdays and they now mix with regular events.
I don't know if this is an intentional change or a bug, but I would for sure like the option to have 2 different toggles for birthdays and events, or at least a setting to hide birthdays from Google in the <my_email>@gmail.com calendar.
I noticed this too and thought maybe it was me so went as far as turning off sync for Google and back on, even removing my account and adding back. The separate calendars are no more and it kind of is a bummer.
Adding an Outlook account still retains the separate personal vs birthday calendars so it is probably something with Google.. maybe Google changed something on their end in APIs?
I'm using an S24 Ultra so it's not device dependent.
