unless you really need it, set up sync to work only on your home network. you enter a new event when away and it stays on your device.

once you get home, it then syncs with radicale/syncthing/nextcloud/whatevers.

before you take the jump, consider a way lighter and easier alternative - syncthing (files) and radicale (calendar, contacts). dependable, bullet-proof, super-lightweight, zero issues - everything nextcloud isn’t.

I was the happiest when I finally booted nextcloud off my network, never to return.