These things aren’t helping you –
- Media is not included in that size-limit. Are there limits on file sizes on AnkiWeb? - Anki FAQs
- Add-ons aren’t synced
But there are several things that you can try that will – Constant Errors Uploading / Sync - #4 by Danika_Dakika .
Are you trying to sync with the AnkiWeb account you just created today? Or do you have another one under a different address?
That should get you under the size-limit very quickly
– but then what do you have left that you want to sync? Just the review history of your empty collection?
What wasn’t working about that?
That is certainly concerning, but I think I know the behavior you’re seeing. It’s usually cured by running Check Database, and it is unlikely that it would cause your collection database to grow over the limit.