Help getting REST API submit-form working?

I am new, so I might be misunderstanding something.

I want to start a process via REST with variables. I haven’t found a complete example. My process that contains this startEvent:

<bpmn:startEvent id="StartEvent_1" camunda:formKey="variables">
      <camunda:formField id="project" type="string" defaultValue="project" />
      <camunda:formField id="boo" type="string" defaultValue="boo" />

My rest call looks like this

const payload = {
  variables: {
    project: { value: 'Example', type: 'String' },
    boo: { value: 'Testing', type: 'String' }

await axios({
  method: 'POST',
  headers: {
    'Accept': 'application/json',
    'Content-Type': 'application/json'
  body: JSON.stringify(payload),
  url: "http://localhost:8080/engine-rest/process-definition/key/my-test/submit-form",

This starts up the process, but then my process calls a remote Java Worker and in the remote Java worker I try to get the variable (code below), the variables are both at the defaultValue value.

client.subscribe("mytest").handler((task, taskService) -> {
  System.out.println("1: " + task.getVariable("project"));
  System.out.println("2: " + task.getVariable("boo"));
  taskService.complete(task, variables);

What am I doing wrong? Is there an example with both the bpmn and the calling code?

Thank you!