Networking for ECS task on Fargate?

I have a batch job, I run its worker instances in parallel in a server that I own. For learning purposes I'm adapting it to run the workers as ECS task on Fargate. I already have my image in ECR, as well as the cluster and task definitions. What's unclear to me is the networking.

This job only needs outbound access to the internet, as well as access to other AWS resources on the same account, and which can be placed in the same VPC, namely an SQS queue. Reading through the documentation, it is suggested to run the task on a private subnet connected to a NAT Gateway on a public subnet, which in turn is connected to an Internet Gateway. This is fine, but then I need a CloudFormation template to create the VPC, both gateways and their subnets, EIP for the gateway, route tables, and so on.

This is a toy project, but I'm trying to treat it as production. Is all of the above the best option for the networking, considering security and SDLC? It's more complicated than I anticipated, and I wonder if it could be simpler. Could it run in the default VPC for my account, and instead of gateways restrict to outbound access only with a security group? Or would that be bad practice from security standpoint? Sorry if it's a silly question, I'm not used to the networking details of AWS yet.