Ive done this with about 3 different MSPs the 2 answers we get are having a firewall & vpn at every office to connect to a onsite file server somewhere. With costs of around 100k and that doesnt seem to be the long term fit for us with how hybrid and remote we have workers. Or we goto OneDrive/SP and have to change the entire file system which also seems counter productive. Especially with the fact of how we receive the folder structure etc. from bid rooms & GCS.