Router is connected to two switches

SX3206HPP 10g

SG2218P 1g

Sending data from a device on 10g to a device connected in 1g is very slow, seems due to congestion and dropped packets.

Setting flow control helps but not reaching the max of what 1g could do.

Is there a way to limit flow on any device on the network that communicates with a specific IP to 1g? -- I am only able to find bandwidth control to WAN.