Job Scheduler kills after swiping the app from recent task in OPPO phones

Question

i came to know that background services are not a way around in order to perform background task instead Job Scheduler was focused more as an alternative

i was applying the job scheduler functionality in my app and i was so confused that why my job is not running as expected whereas in android emulator it is running smoothly

below is my code which i have applied so far

Java.Lang.Class javaClass = Java.Lang.Class.FromType(typeof(jobsched));
            ComponentName component = new ComponentName(this, javaClass)
            JobInfo.Builder builder = new JobInfo.Builder(999, component)
                                                 .SetMinimumLatency(1000)   // Wait at least 1 second
                                                 .SetOverrideDeadline(5000) // But no longer than 5 seconds
                                                 .SetPersisted(true)
                                                 .SetRequiredNetworkType(NetworkType.Any);
            JobInfo jobInfo = builder.Build();
            JobScheduler jobScheduler = (JobScheduler)GetSystemService(JobSchedulerService);
            int result = jobScheduler.Schedule(jobInfo);
            if (result == JobScheduler.ResultSuccess)
            {
                // The job was scheduled.
            }
            else
            {
                // Couldn't schedule the job.
            }

And Scheduler service

 public override bool OnStartJob(JobParameters @params)
 {
     Task.Run(() =>
     { });

     JobFinished(@params, true);
     return true;                                                        
 } 
   public override bool OnStopJob(JobParameters @params) {
            return true;
        }

above scheduler seems to work fine when the app is open but when the app is closed by swiping away from recent task it doesn't notify me any more

i am missing something, please help me with this