As you might have seen they've added a cloudflare captcha which breaks spdl.

I don't know if there's some way around it but in the meantime I've found that if you go on spotifydown and do all the process to the download, the download will have a token at the end I was able to successfully add it to the url and re-use it to sync all my playlist

def  get_track_info(link):
    track_id = link.split("/")[-1].split("?")[0]
    token = "long_token_string"
    response = requests.get(f"https://api.spotifydown.com/download/{track_id}?token={token}", headers=CUSTOM_HEADER)
    response = response.json()

    return response

It's not the ideal solution but it's still much better than doing everything by hand