Transfering RS485 data to server using ethernet
Any medium-range micro-controller should be fine communicating with the meters. Well, you don't said what is the protocol used at the meters, as RS-485 does not imposes one. Fieldbus does CRC calculations that are more intensive, but it should not be a problem.

As the mentioned products does not have Ethernet PHY embedded then you will use:

Meter - RS485 transceiver - (UART/micro-controller) - Ethernet PHY - Ethernet network

For the RS-485 transceiver you could use a MAX485 for example.

The majority of work is at the TCP/IP stack.

How you would upload your data is a broad topic and has so much solutions. You could develop a protocol of your own, and have optimized bandwidth usage. But this requires a
study at the protocols involved.