How to remove byte to byte delay using MCP2210
You don't say what that delay is, but page 38 of the datasheet (https://ww1.microchip.com/downloads/en/DeviceDoc/22288A.pdf) has settable parameters at offsets 16-19 that may resolve your issues.

A quick scan of the data sheet shows four or five High Byte/Low Byte pairs for registers with the label &quot;Delay Between Subsequent Data Bytes&quot;.  You should check them all.