My device is Wileyfox Swift on Leanage OS 16 with MicroG (16.0-2019-1021-microG-crackling). DAVx5 2.5.5-ose (302) from the F-Droid market.
The issue is the stock Calendar application see no my calendars. Also I tried a couple of calendar apps from F-Droid, but also without any success.
There is DAVx5 log and logcat taken while I opened the Calendar app and tried to update list of calendars: