Trouble accessing REST APIs with VPC Link for my EKS cluster - Seeking assistance and potential solutions

Greetings to all.

I hope all is well with you. I am having a problem right now, and I think this might be the best place to get it fixed.

I've got an EKS cluster running behind an ALB (application load balancer), and I've deployed one microservice with the service type "LoadBalancer" The rest of the microservices are running as a "ClusterIP" service type. Now that I want to make it accessible through API Gateway, I created a microservice with the service type "LoadBalancer"; as a result, I now have a Classic Load Balancer in my Load Balancer Section. Currently, I am accessing my application using the same CLB's DNS name, and it is working just fine, for example, LoadBalancerDNS:ApplicationPort/Path. In order to use API Gateway with VPC Link for my REST APIs, I have now created an NLB. I did this by migrating the same CLB to the NLB, adding a listener for my application port (3000), and choosing the same CLB as a target group. Now, whenever I try to configure the APIs as a VPC Link and choose the identical VPC Link ID that is connected to the NLB as mentioned above, I either receive a 500 status code or a 404. I have also tried using the application load balancer (ALB) that we use for EKS, and if I add the ALB as a target group for the NLB, I still experience the same issue.

To access my REST APIs with VPC Link, which is running on an EKS cluster, please let me know if there is anything wrong with what I am doing or the potential solution to accomplish this.

P.S. - The Solution should be in a detailed way.