@EA_David In the same boat of having missing dlcs despite owning the GOTY edition on steam 'supposedly' with all the dlcs. Originally played through the steam EA Play membership and wanted to buy a full copy of game during the sale on steam (big woops) turns out steam version and origin version are very different and now it won't accept the dlcs I've reinstalled twice.
1) never played with mods
2) already removed ea play copy from steam account
3) repaired the game twice on origin and steam
4) unticked and ticked those dlc boxes
5) reinstalled my steam copy twice now
If you were wondering dave my App ID is 1222690 and Build ID is 0 (doesn't sound right but it is). I have read cases where ea support have had to add the game to other people's origin accounts as well as adding the correct steam version to their account which solved their product key issue.