Is there a limit on the number of uploads per project?

Yes, the number of allowed uploads per project depends on your subscription plan:

• Free projects:
  10 images,
  3 videos ( up to 100MB and 20sec each),
  3 audios
• Creator projects:
  10 images,
  5 videos (up to 500MB and 40sec each),
  5 audios
• Pro projects:
  50 images,
  50 videos (up to 1000MB and 120sec each),
  50 audios
• Agency projects:
  150 images,
  100 videos(up to 1000MB and 120sec each),
  100 audios