How do I mount a Synology remote folder on Android 8.0?
No specific configuration beyond the availability of published shares is required.

Sometimes issues arise due to the stability and capabilities or lack thereof of Android apps to mount the shares. The following apps have been tested and were able to reliably and successfully access SMB shares from the Synology server (at 2 June 2020) using a simple combination of (server) IP Address, username and password:

LAN drive, Cx File Explorer, X-plore, File Commander