daffy
I can answer the Calendar question based on my experience.
Signing into Google Play will add a Google account in Accounts and Password and Google contacts will be able to synchronize. However, this is not the case for Google calendar. You need to install the Google Calendar app and then you can use Simple Calendar and Etar to "read" your Google calendar.
Alternatively, you can use DAVx5 which acts as a CardDAV and CalDAV client if you don't want to add/install the Google account and Google Calendar app on your phone.

      daffy What happens if I have two different Private DNS, one in Vanadium on in Android settings

      You can test this by going to dnsleaktest.com

      daffy I have installed sandboxed Google Play Services but if I disable location permission Here Maps and Organic Maps are unable to lock on GPS which is weird considering that Organic Maps works without Google Play Services.

      It may be that Organic Maps is detecting Google Play Services and is "trying" to use it for better location accuracy. Does it work if you disable/uninstall Google Play Services?

            For what it's worth, I found a calendar app that lets me sync to Google Calendar without linking the operating system to a Google Account - it just directed me to a webpage to login. It's called OneCalendar and it's available from Play Store/Aurora Store.

              Teilkasko Thanks for reply. Point is to have actual account that syncs so I have same appointments in all of my devices. It is also important for shared appointments.

                daffy
                I bet you can. That app is just a connector, a middle man, you still need a Calendar app.
                And you need some preparation work, e.g. creating an app password, obtaining the Calendar ID (CalID), etc.
                See here the "tested" by DAVx5 - https://www.davx5.com/tested-with/google

                DAVx5 is so popular and great, so you can easily find tutorials all over about how to use it.
                Here is a quick example - https://www.reddit.com/r/fossdroid/comments/faxydl/howto_sync_google_calendarcontacts_with/

                    Graphite DNS leak website has shown DNS set on Vanadium. Disabling and enabling all three Google apps (framework, store, services) worked fine and both OSMand and Organic Maps can now lock on my location without Google services. Organic Maps has a little pause before finding me but OSMand is instant like Where Maps and Google Maps using services.

                    Thanks.

                      mumbo6868 I don't like data collection policy of the app that you recommended but thanks anyway. I have found aCalendar+ having no data collection + having actually tasks sync compatible with both Google and Nextcloud very good. Best I found so far.

                        [deleted] I'm ProtonVPN user for a long time. Other three apps I found problematic because they don't support this'd party account syncing which means that if I chose them I will need to install additional apps that will do the same thing. They need to uncouple apps from their services for me to use them.