Deploy gRPC supporting application on AWS using ALB

I don't believe you can.

ALBs "support" HTTP2 but only in so far as they can accept HTTP2 and de-multiplex it before forwarding on HTTP1.

You can use AWS's newer "NLB" though that has other wrinkles. More details of doing this https://blog.prefab.cloud/blog/grpc-aws-some-gotchas