Problem Accessing Network Shares within Debian 10.3

I recently upgraded from Debian 9.x to Debian 10.3. Once installed, I discovered that I could no longer mount the network drives to my computer as I had in Debian 9.xx. I was finally able to mount the drives by including the "vers=3\.0" parameter/option in the mount command. Now I can mount and read the contents of the shares, but I cannot write to them. "ls -all" says everything is owned by root. I tried chown (as root) to change the ownership to my user account, which was apparently successful. Unfortunately, when I checked everything was still listed as belonging to root. The chown command had no positive effect.

What is going on, and how do I get Debian 10.3 back to the functional level that I had with Debian 9.xx?

Thank you everyone who assists!

brucem