func main() {
	dynamicConfig, err := config.NewConfigCenterConfigBuilder().
		SetProtocol("zookeeper").
		SetAddress("127.0.0.1:2181").
		Build().GetDynamicConfiguration()
	if err != nil {
		panic(err)
	}
	if err := dynamicConfig.PublishConfig("dubbo-go-samples-configcenter-zookeeper-client", "dubbogo", configCenterZKClientConfig); err != nil {
		panic(err)
	}
	config.SetConsumerService(grpcGreeterImpl)
	rootConfig := config.NewRootConfigBuilder().
		SetConfigCenter(config.NewConfigCenterConfigBuilder().
			SetProtocol("nacos").SetAddress("127.0.0.1:2182").
			SetDataID("dubbo-go-samples-configcenter-zookeeper-client").
			Build()).
		Build()
	if err := rootConfig.Init(); err != nil {
		panic(err)
	}
	logger.Info("start to test dubbo")
	req := &api.HelloRequest{
		Name: "laurence",
	}
	reply, err := grpcGreeterImpl.SayHello(context.Background(), req)
	if err != nil {
		logger.Error(err)
	}
	logger.Infof("client response result: %v\n", reply)
}
There is no need to export DUBBO_GO_CONFIG_PATH, as you are using config api to set config
package main
import (
	"context"
)
import (
	"dubbo.apache.org/dubbo-go/v3/common/logger"
	"dubbo.apache.org/dubbo-go/v3/config"
	_ "dubbo.apache.org/dubbo-go/v3/imports"
)
import (
	"github.com/apache/dubbo-go-samples/api"
)
const configCenterZKClientConfig = `## set in config center, group is 'dubbogo', dataid is 'dubbo-go-samples-configcenter-zookeeper-client', namespace is default
dubbo:
  registries:
    demoZK:
      protocol: nacos
      timeout: 3s
      address: 127.0.0.1:8848
  consumer:
    registry-ids:
      - demoZK
    references:
      GreeterClientImpl:
        protocol: tri
        interface: com.apache.dubbo.sample.basic.IGreeter # must be compatible with grpc or dubbo-java`
var grpcGreeterImpl = new(api.GreeterClientImpl)