My desktop C: suddenly became full ("TDiskDB: The database disk image is malformed" error message) and I couldn't figure out why, until windirstat told me networx.db file is 30 GB. I recently just updated to version 6.2.10.
In this 2019 thread, it's mentioned to use "ignore local traffic" and that this issue was fixed in the upcoming update. Doing that disables SNMP monitoring. On my server/nas, networx.db is 14 MB, it's also running 6.2.10 and monitoring through SNMP.
The issue with exceedingly large database files has been fixed in the newer NetWorx releases.
Most likely, you had earlier NetWorx versions on your local machine, and that 30 GB file was created by one of them. Whereas on you server you probably started using NetWorx beginning with one of the newer "fixed" versions, and therefore the file is kept to a much smaller size.
If you don't mind losing old usage data reports, the database file can be deleted when NetWorx isn't running. Copying the database file from another machine, as you did, is also a perfectly valid way (again, exit NetWorx application before doing that). In this case you will see previous usage statistics from the other machine.