Hmmmm ... NDA.
From what you have described so far (really not much technical detail, but good enough for guesses), sounds like server may not have enough 'umph' for GUI backup/restore.
So what are server specs .... like memory/space etc. As well as set up ... all on one server? Dedicated DB server?
If you find you have ssh access and can install software, consider installing moosh - a cli tool outside of Moodle code. It has backup as well as restore.
And, just so you know, I admin a K12 server ... there have been courses as large as 130+ Gig .... a few 50Giggers and many are in the 20+ Gig range. For those, can only do CLI backup. This to say 1-2 gig ain't that large! ;)
Those large courses I mentioned were backed up ... over a weekend .... and with CLI only with &nohup!
How did you determine courses were of that size?
Sounds also like courses are SCORMS ... I hope they are HTML 5 compat and not still SWF.
Are you using file system repos for those SCORM's and linking via 'aliases'?
'SoS', Ken