Calendar & scheduling

Here is a list of open-source alternatives to Google Calendar, Calendly, Outlook Calendar, Doodle (calendars and booking meetings), from Open Source Everything (CC BY-SA 4.0): - Nextcloud Calendar (AGPL-3.0, https://github.com/nextcloud/calendar; replaces fully): A calendar app that runs on a Nextcloud server, letting you sync events from your devices and edit them in a web browser. It is for people and teams who want to keep their calendar on their own Nextcloud server. - Cal.com (MIT, https://github.com/calcom/cal.com; replaces partly): Cal.diy is the free community edition of Cal.com, which lets you share a page where others pick a meeting time. It is for people running their own server, and the makers advise it for personal use only. - Etar Calendar (GPL-3.0, https://github.com/Etar-Group/Etar-Calendar; replaces partly): Etar is a calendar app for Android phones that shows month, week, day and agenda views. It is for people who want a simple calendar that can keep events on the phone or sync them with a calendar server. - Fossify Calendar (GPL-3.0, https://github.com/FossifyOrg/Calendar; replaces partly): Fossify Calendar is a calendar app for Android phones that lets you plan events, reminders and repeating appointments. It is aimed at people who want a private calendar with no ads or tracking. - Nextcloud Polls (AGPL-3.0, https://github.com/nextcloud/polls; replaces partly): Polls is an add-on for Nextcloud, a self-hosted file and collaboration server, that lets you create polls to find a meeting time or pick options. It is for people and teams who run their own Nextcloud and want to schedule without Doodle. - Tymeslot (AGPL-3.0, https://github.com/Tymeslot/tymeslot; replaces partly): Tymeslot is scheduling software that lets people share their availability and let guests book meeting times. It is meant for individuals and teams who want to run their own booking system on their own server. - Thunderbird (MPL-2.0, https://www.thunderbird.net; replaces partly): Thunderbird is a free, open-source email app for Windows, macOS and Linux that also includes calendars and contacts, with an Android app for email. It suits people who want to manage their email and calendars in one desktop program without relying on a big tech company. Compare it with my project or idea below. Tell me which projects overlap, what I could reuse instead of rewriting, and what mine does that none of them do. My project or idea: