Is there another way to download and install updates when no WiFi available?

App updates, yes (setting for downloads in the iTunes & App Store settings panel) but not iOS updates. The iOS update system still requires a WiFi network. A cellular MiFi node will work though as your device connects to the MiFi router over WiFi.

You can install Updates using Cellular Data. (Data Charges may apply).

You cannot use cellular data for iOS updates. iOS Over the air updates require a wifi connection.

App updates in iOS 13 can be done over cellular data, regardless of update size.