We rely on Intervals for all our integrations and currently Intervals does not have a direct integration with iGPSPORT or Bryton. However there is a free and open source community plugin called ‘Intervals.icu Sync Tools - Free and Open Source‘ that can sync our workouts to iGPSPORT or Bryton via intervals and also receive activities from those devices.
We have not tested it ourselves nor officially endorse it but you can study their post and give it a try if you want.