[dotancohen]

The calendar app uses the internal Android calendar service, which can be synced via Davx. I sync mine with NextCloud.

[sureglymop]

In that case why don't you sync your calendar with Nextcloud directly using CalDav? I use DavX5 for this and it works great, actually i think DecSync is a fork of DavX5.

[dotancohen]

That is exactly what I do.