Thank you for the quick feedback!
I just tried again from Ubuntu and got the same error message:
(transformers) guillaume@guillaume-MS-7B78:~/gpt-neo-1.3B$ transformers-cli lfs-enable-largefiles .
Local repo set up for largefiles
(transformers) guillaume@guillaume-MS-7B78:~/gpt-neo-1.3B$ git lfs track rust_model.ot
Tracking "rust_model.ot"
(transformers) guillaume@guillaume-MS-7B78:~/gpt-neo-1.3B$ git add rust_model.ot 
Encountered 1 file(s) that may not have been copied correctly on Windows:
	rust_model.ot
See: `git lfs help smudge` for more details.
(transformers) guillaume@guillaume-MS-7B78:~/gpt-neo-1.3B$ git commit -m "Addition of Rust model"
[main 094438a] Addition of Rust model
 1 file changed, 3 insertions(+)
 create mode 100755 rust_model.ot
((transformers) guillaume@guillaume-MS-7B78:~/gpt-neo-1.3B$ git push
Username for 'https://huggingface.co': guillaume-be
Password for 'https://guillaume-be@huggingface.co': 
Username for 'https://huggingface.co': guillaume-be                                                    
Password for 'https://guillaume-be@huggingface.co': 
EOFoading LFS objects:   0% (0/1), 5.0 GB | 0 B/s                                                      
error: failed to push some refs to 'https://huggingface.co/EleutherAI/gpt-neo-1.3B'

I tried with and without the step git lfs track rust_model.ot, getting the same error both times. Unfortunately troubleshooting is time-consuming given the upload takes ~1 hour.
edit: I just tried the upload again with GIT_TRACE=1 GIT_CURL_VERBOSE=1. Coincidentally, I am trying to upload ~5.3GB which should take just over an hour to complete. The upload crashes towards the end of the upload - but I believe this could very well be due to a timeout. Looks like the git worker below sets a "expires_in": 3600 that exactly matches 1 hour.
Is there a setting on server side (or something I should change on my side) to allow for uploads taking longer than an hour?
18:06:53.358398 trace git-lfs: xfer: Custom adapter worker 0 sending message: 
{
  "event": "upload",
  "oid": "[...]",
  "size": 5312743379,
  "path": "/home/guillaume/gpt-neo-1.3B/.git/lfs/objects/cc/d3/[...]",
  "action": {
    "href": "https://huggingface.co/EleutherAI/gpt-neo-1.3B.git/info/lfs/objects/complete_multipart?uploadId=[...]",
    "header": {
      "00001": "h[...]",
      "00002": "[...]",
      "chunk_size": "5000000000"
    },
    "expires_at": "0001-01-01T00:00:00Z",
    "expires_in": 3600
  }
}