Using temporal credentials from STS when role chaining through multiple accounts

[tester4x4]

Hey there, thanks for your amazing contribution to the open-source world.

Is there any function helper or implementation which enables to assume credentials from another account using some temporal sts credentials?

I am using:

"github.com/aws/aws-sdk-go/service/sts"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/aws/credentials"

(from: https://plainenglish.io/blog/aws-iam-role-chaining-df41b1101068)

Is it possible to use those "temporary creds 1" to assume a role located on account2?

What I've tried is:

for i := 0; i <= len(account.Role); i++ {
    if i == 0 {
        result, _ = svc.AssumeRole(&sts.AssumeRoleInput{
            RoleArn:         &account.Role[i],
            RoleSessionName: "test",
        })
    } else {
        fmt.Println("assume role on account 2 with temporal credentials from account 1")
        result, _ = svc.AssumeRole(&sts.AssumeRoleInput{
            RoleArn:         &account.Role[i],
            RoleSessionName: "test",
        })
    }
}

Where account.Role is a slice such as [arn:aws:123:role1/role1 arn:aws:321:role2/role2]
Then the preceeding logic is as follows:
1- Assume starting role from account.Role slice, with the actual credentials from the account 1 (mentioned in picture)
2- Use the temporal sts credentials obtained from step 1 and call the assume role operation on account 2 with this creds.

It is faling with:

AccessDenied: User: arn:aws:iam::123:user/role1 is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::321:role2/role2
        status code: 403, request id: e211a4a5-2cdd-456a-acb1-6877a0ab22d0

As you can see, it is not grabbing and using the temporal credentials generated on the step 1.

Is there any smart way of achieving this?