According this post ~800Mbps should be achievable with NanoPi R2S
I recommend to invest some time in optimizing your current setup to squeeze every last bit of performance.
=> Best is to start a new topic, provide current config and list your goal like maximizing throughput or optimizing for a balanced throughput/latency
collecting current config
Connect to your OpenWrt device using ssh , copy output of below commands and post it using the preformatted text button (redact passwords, MAC- and public IP addresses)
ubus call system board
cat /etc/config/network
cat /etc/config/dhcp
cat /etc/config/firewall