Ok, what a few crazy days exploring options!
Keeweb deb would not install. The appimage did! Keeweb Nextcloud installed.
Keeweb desktop could import my csv export (but displayed it incorrectly) The app would not connect to Nextcloud. It turns out the project has been unmaintained for over 2 years.
I could export a backup from keeweb desktop a kdbd file for the keepass profile though. I opened the desktop backup in Keeweb Nextcloud. Both desktop app and browser look great - but do not communicate.
I then uploaded the kdbx file to Nextcloud files.
Exploring other apps I found Authpass desktop and Android app to be the best. There is no automatic sync however. This has to be triggered manually from whatever app you are on.
After trying to activate the Nextcloud file kdbx for Nextcloud Keeweb I eventually managed to click in the right place. So now I had the desktop, cloud and phone working together, well, when manually triggered that is!
Now to sort out the wrong formatting! After installing many app and messing about with python scripts I could not get the data fields right. Keepass2 app suppose to have an import function. It was greyed out. I uninstalled it, but later came back when I learnt that you needed to create a database first before importing onto it! I chose a Bitwarden json - and it worked!
Ok, going well! Now I just need a browser extension! Fail! None could grep the kdbx file from Authpass or Nextcloud! At least none that could create passwords! This is actually my main point of interaction with passwords. An essential component.
So, I have actually ended backup where I started - using Nextcloud Passwords! I cleared up one annoyance sort of. That was, that every time I used biomemetrics to open the Android app it then also asked me TWICE to enter my password! I switched to pin and I only have to enter it once.
The Nextcloud desktop app, which is actually still a work in progress, is the only sore point. It opens tiny and the geometry cannot be set as it does not use the KDE window rules. The UI is awful and I need to go to settings - themes to change the theme in order to see the text. There is no search or export/backup. It is near useless at this point. Hopefully it will develop!
If only they would fork Keeweb desktop! It is full featured and beautiful! More beautiful than all the other Keepass apps and better looking that Bitwarden also.
nb.I never got to test out Passman.
Yeah, it seems like such an unnecessary layer! Why login to your desktop, phone etc then have to login to a server also? I prefer to just open an application that has the feeds direct from source!