That worked, but somehow no SMB errors visible in the logs, only thing I see is that you use DNS/Netbios names for the shares which some people has reported to have issues with…
You might need to enable “component specific logging” for SMB.
But to be honest I am not sure if it maybe easier to go for fstab based mounting of SMB shares which would make it easier and more performant.
If you don’t want to switch to fstab based samba share you also could try this