The KeePassXC developers are quite conscious about memory security and implement that in XC in a way that's not really possible with a .NET application like KeePass: https://keepassxc.org/blog/2019-02-21-memory-security/

KeePassXC supports TOTP. This is the main reason why I switched.

Arguments sound good but I didn't seem to find any biometric authentication for KeePassXC. In KeePass I could use some plug-ins to connect Windows Hello with KeePass so I could unlock the DB with my fingerprint or via looking into the camera.

Maybe I simply didn't search good enough, is there any possibility to have such functionality in KeePassXC?

There are some nice quality of life features; the "auto-save" being the one I use the most. So my changes don't get lost, and they get synced (for me via Syncthing) virtually immediately.

I find the browser integration extension(s) more robust/stable as well, but that could be environmental.

Not really. I use KeePass on Windows and KeePassXC on macOS for the same password db that I have cloud synced.