You could either do the Steam version, or the Ubisoft version.
https://store.ubi.com/us/game/?lang=...&source=detail
both will watch the other's pricing, and they usually stay competitive with each other in that regard, sometimes going down to $3 a copy...
It would be much much easier doing the Gold Edition that way, than having to attempt to apply all the updates and patches, and still having to contact Ubisoft for your U-Boat Add-On authorization every five installs...