Can't see NAS (SMBv1), even via IP address (tried common solutions)

@Blaq ... FWIW ...
You can find out which SMB Version/Dialect Win10 is actually using when connecting to your NAS and Other PC's. It requires you have an active connection to Share Folders.
1. Open PowerShell as Admin
2. In File Explorer > Network > Open a shared folder on your NAS and your other Win10 PC
3. In the PowerShell Window run the command get-smbconnection
4. The Dialect is the SMB Version (i.e. mine is using SMBv3 ... Dialect 3.1.1 ... in the example below)
5. Yours should/will probably be SMBv1 (Dialect 1.1.1) for your NAS Shares and SMBv3 (Dialect 3.1.1) for you Win10 PC Shares.

Code:

PS C:\WINDOWS\system32> get-smbconnection

ServerName  ShareName  UserName        Credential      Dialect NumOpens
----------  ---------  --------        ----------      ------- --------
192.168.1.1 ShareDrive EAGLE-HPL\ EAGLE-HPL\ 3.1.1   1
192.168.1.4 TempFiles  EAGLE-HPL\ EAGLE-HPL\ 3.1.1   1
192.168.1.4 User       EAGLE-HPL\ EAGLE-HPL\ 3.1.1   1
192.168.1.4 www        EAGLE-HPL\ EAGLE-HPL\ 3.1.1   1
EAGLE-HPD   IPC$       EAGLE-HPL\ EAGLE-HPL\ 3.1.1  
EAGLE-HPD   TempFiles  EAGLE-HPL\ EAGLE-HPL\ 3.1.1   1
EAGLE-HPD   User       EAGLE-HPL\ EAGLE-HPL\ 3.1.1   7
EAGLE-HPD   www        EAGLE-HPL\ EAGLE-HPL\ 3.1.1   3


PS C:\WINDOWS\system32>

Note:
1. Connected Mapped Network Drives will automatically show since they are active connections. You can tell mine in the above example, because I use Static IPs and Map Network Drives by IP ... You may or may not have mapped network drives.
2. The others using PCNAME are the ones I manually went to in File Explorer > Network > ShareName
3. I've removed my UserName from the above output. You don't need to post your result, but if you do remove your UserName.