Selfhosted or alternative privacy driven google calendar? - Lemmy.world

Hi everybody ! While I really like the simple and sleek google calendar web GUI and functionalities, I’m more and more concerned about my data and privacy. Even if I have nothing to hide, I don’t agree anymore to sell freely and consciously my data to any GAFAM. Has anyone any alternative to google calendar? - Free and if possible, open source? It can have some discret sponsors/ads. As long as it isn’t to intrusive. - Todoist integration - Sync between devices - GUI doesn’t have to be PERFECT, but a bare minimum for my candy eyes ! - Can be API, Web… doesn’t matter as long as it syncs between devices (android, mac, windows, linux) I already searched through the web, but couldn’t find any conclusive alternative, maybe someone knows some hidden gem :) Thank you !