Due to a problem with the Intel® Quartus® Prime Software, the 1G/2.5G/5G/10G Multi-rate Ethernet PHY Intel® FPGA IP has incorrect type of interface for the rx_digitalreset and tx_digitalreset signals, therefore you cannot connect these two signals to the Transceiver PHY reset controller Intel FPGA IP in the Platform Designer. The correct type of interface for the rx_digitalreset and tx_digitalreset signals are conduit NOT reset.
Export the rx_digitalreset and tx_digitalreset signals from the Platfrom Designer and manually connect at register transfer level (RTL). This problem is fixed starting with the Intel® Quartus® Prime Pro Edition Software version 18.1.