Selfhosted

I am actually in a clinch with my nextcloud experience and found some different ways to handle this. My plans (tests looks good) is to simply use a small free nextcloud provider just to handle caldav/carddav/notes and stuff without all my data. Just enough to get everything synced.

For my data I plan to use ocis. It's a long year rewrite of owncloud getting rid of PHP and hassle. It's just a single binary. Docker support, too, but it needs some extra steps to initiate, unfortunately. But the experience is fast, modern, clean and simple. Without to much bloat.

For Kanban I use wekan, because it has more features. Nextcloud I host using snap, which I cannot 100% recommend because it sometimes has troubles upgrading to the latest version. Still, for me it causes less trouble than a manual install.

cryptpad si quite good

I dont know about kanban but the other stuff can be achieved via webdav. All major webservers can do that or you just use filebrowser.org (a selfhosted webdav server with built-in user management).

Wdym nginx is not supported? It very much is. Nextcloud is a pain to set up but after fiddling with settings for a day or two you can get it working smoothly. In my experience there are no good alternatives to it.

Synology is the answer.