Azure DevOps indeed does have some certain limitations as far as the repositories are concerned. For any project that is private or public, the size of the repo should not be greater than 250GB. Incase if your repo is greater than 250GB you won’t be able to check in more files to that particular repository.
And the optimal recommended size by Microsoft is 10GB for any repository. Even if you repository exceeds, you should try switching over to Git-LFS or Scalar or reduce your repository. In addition to that, there is something called packs which Azure DevOps uses to group similar files, if the internal limit on pack is reached then user would be seeing the following error message
The Git pack file limit has been reached. write operations are temporarily unavailable when the repository is updated.
The above error message would appear till the optimization process is completed. Once its completed the write operations will be restored immediately.