Below is a link about configuring smb multichannel in Windows:
smb multichannel worked seamlessly for me on a MacBook Pro with two usb c 1 Gb ethernet adapters connected to two 1 Gb ethernet ports on the Synology. smb multichannel was default enabled by the Mac. I got transfer speeds copying data to the NAS of up to 245 MB / sec, which is almost 2 full Gb / sec!