Nextcloud is a fantastic Software for storing and sharing Files plus PIM- Data. With Nextcloud All In One (AIO) you can even have your own private Hosting of Videocalls plus dozens of Features for Teaming without any other Company beiing involved.
As you do have Docker running as described before, you can easyly install a running Instance of Nextcloud to you PC. Heres the original doc: https://github.com/nextcloud/all-in-one
As i do have IPV6 only to reach the server, it is very important to set up networking the right way to make nextcloud-aio work.
Per default, only ipv4 networking will be set up by nextcloud-aio. So the setup will check the adress and will fail.
Further you need to have a network, that is called exactly „nextcloud-aio“ with ipv6.