Finalized forms taking too long to upload

I have a survey on a humanitarian project and and forms have been deployed and completed by enumerators, but I am presently experiencing a very very slow speed of upload.
I have done a couple of troubleshooting but still, there hasn’t been any much improvement.
Is this an internal issue? or is it because the size of the form might be large due to pictures taken for each respondents.
Lastly, what is the limit for humanitarian organization for the number of forms to be deployed on Kobo and the number of data that can be housed and any tips on how to improve upload speed?

Looking forward to your various contributions.