Change <vpn-name> with your VPN's name.
# IPv4
curl --silent https://ip-ranges.amazonaws.com/ip-ranges.json \
  | jq -r '.prefixes | .[].ip_prefix' \
  | tr '\n' ',' \
  | sed 's/,$//' \
  | xargs nmcli connection modify <vpn-name> ipv4.routes# IPv6
curl --silent https://ip-ranges.amazonaws.com/ip-ranges.json \
  | jq -r '.ipv6_prefixes | .[].ipv6_prefix' \
  | tr '\n' ',' \
  | sed 's/,$//' \
  | xargs nmcli connection modify <vpn-name> ipv6.routes