SW2 needs to be ON - that “Enable Broadcast Storm” means it will allow multicast packets to operate transparently, this is necessary for the dCS Network Bridge and Mosaic to work properly.
SW1 - I’d also recommend to be ON - otherwise you might not be aware of Ethernet cable faults in your home setup.
SW3 and SW4 at OFF - let the ports auto-negotiate.
On your S100, I’d recommend sticking to using just ports 5, 6 or 7 for your uplink to your main Router. Don’t bother with ports 1-4 as they’re fixed to just 100Mbps - the proclaimed benefits are bogus, those ports are there only because the Broadcom chip used in the S100 comes with them for network backward compatibility.
I’m not sure if that’s going to properly fix your problems, but give it a try, good luck.
Regarding the S100, I prefer my streamers (Rossini and Aurender N10) connected to ports 1-4 (100Mbps), it’s not a huge difference to the 1000Mbps ports but there is a slight SQ advantage in my system.