The ideal way to solve this is with queues. You pass long running tasks to the queue and it processes in the background.
Wappler doesn’t have that built in, but maybe another vote here will help. 
Without a queue, you can use the scheduler or cron jobs. This works but is not as immediate in its processing. You basically have a table for these “jobs” and insert a new job into the table when the user submit the form.
The job record has all the information that will be needed to perform the tasks—user-id, type of job, other parameters, etc.
The scheduler or cron then searches the jobs table periodically for anything not yet processed and performs all the api calls etc. and ultimately sets the job record as completed so it is not performed again.