What causes some Network Drives using SMB no longer connect to macOS Catalina?
The solution is in Catalina release note

https://developer.apple.com/documentation/macos_release_notes/macos_catalina_10_15_beta_2_release_notes

NetBIOS is disabled in macOS 10.15 to speed up mounting, browsing, and connecting to SMB shares. Some older printers and file servers may require NetBIOS to connect. (51119111)

To enable NetBIOS, you can create or edit the /etc/nsmb.conf file. If your system doesn't already have an /etc/nsmb.conf file, use the following Terminal commands while logged in as an Administrator:

echo "[default]" | sudo tee -a /etc/nsmb.conf
echo "port445=both" | sudo tee -a /etc/nsmb.conf


To disable NetBIOS, you can safely delete the /etc/nsmb.conf file.