I have played Destiny 2 since launch on Ps4 and only a few weeks ago got a new pc. I understand that next week, Tuesday is the day of button pushing for the move to Steam linking BNET and steam. I also understand that next Wednesday is the day of button pushing for account linkage AKA cross save. Do I need to wait to cross save before linking BNET and steam? I don't want my pc characters moved over to steam, I want my ps4 characters moved over to steam.
There is no link happening between Bnet and Steam. It is a full account migration to Steam, as D2 is leaving the Bnet platform entirely. When that happens, I believe the licenses to whatever versions of D2 you own and well as the DLC will migrant as well. To be cautious, wait until you are 100% migrated to Steam, and that all of your licences made the trip as well. After that, you should be safe and clear to set up Cross-Save.