KashCal — Community App Review
Version: 23.7.53
Stable calendar with built-in DavX-sync support and ability to directly sync with iCloud, Nextcloud, etc. Can also directly add new ICS subscriptions (and disable them from syncing).
Not optimized for eInk screens, but the various views look great to me. Before using KashCal, I had been using Etar and Fossify. KashCal is by far the superior calendar app and is being actively supported and updated.