If you have the base game and the expansions, you technically have the same content as the GOTY Edition. The only difference is the Title.
That's not 100% true. The main menu in the GOTY edition is different from the main menu of the standard version with all DLC : the entry "Downloadable content" doesn't exist anymore in the GOTY edition, the DLC options (alternative outfit for Ciri, Triss and Yennefer, additional Gwent cards) have been moved into the game options, and the main menu display change at each launch of the game.
This is a pain for the modders and oblige CDPR to maintain two software branches for the same product, with as result versions that do not have the same content with the same number (1.31 standard and GOTY are different).
I agree with Kobi_Blade that CDPR should grant to standard users access to the GOTY edition, with the goal to unify the two complete products in the future. If not, at least they should modify the standard version to unify the main menu and the integration of the 16 free DLC, as on the GOTY version.