The safe bet would be to just buy the non-steam PC version since I'm unsure if the steam will work in this way. I'm pretty sure it will but don't take my word on it. If you buy the complete edition on PC and you only have ARR on your PS4, then if you ever decide to play on PS4 in the future, you will only be able to play ARR content. If you buy steam, you will have to buy steam expansions in the future. Is the steam version cheaper than the vanilla PC version? If not, I'd recommend not buying the steam version. Too many headaches from what I see here on the boards.