Linux – which Linux command allows to browse all available smb shares in the network

I've found out if I either

(1) disable the DNS Relay option on the "Local Network" tab and manually set valid DNS servers such as Google's 8.8.8.8 and 8.8.4.4

DNS Relay means in this case that all your machines send their DNS queries to the relay. The relay sends the queries to the DNS server of the provider or whatever is set in the router's WAN settings.

When it receives the answer it sends it back to the machines and stores it for a short time. So if another machine in your network searches for the same address, it will receive the answer directly from your router without asking internet servers again. (So there is a little memory which remembers the queries - so called: DNS cache)

or

(2) Keep DNS relay enable, but disable the "DNS" option on the "PPPoE" section of the "Internet Setup" tab, and manually set and manually set valid DNS servers such as Google's 8.8.8.8 and 8.8.4.4

then it will work.

This answer takes care of the "how to fix it", but I have absolutely no idea of what is going on.

Did you make a network share (shared folder) on your Linux machine. - If no share is defined, the linux machine (and workgroup) doesn't show; unlike Windows, that shows C$, printers etc. Also allow some time after booting, for Windows network and Samba server to find each other. - Hope this wil help you.

Btw computers are still on the same network, even if you are using different workgroups. They do not need to be in the same workgroup to communicate, share etc.