Hi, first time poster.
I used to use Keepass (still have it as an offline backup) from memory you can't upload a CVS file to KeepassDX (may have changed since my last use). You may want to install KeepassXC on your desktop machine prior to jumping into KeepassDX and go from there.
Below is a link to a tutorial on a way to transition over, hope this helps to some degree.
https://m.youtube.com/watch?v=jL7gfM27EUA