Having FB Plat until Nov 2023 means that you will at least have Gold until Nov 2024. This gives lounge access on international itineraries, as well as extra luggage.

With the projected flights you won’t be able to keep FB Gold status beyond Nov 2024, unless you fly business class. Assuming you fly mainly economy, those flights won’t be enough. However this likely also is the case with Delta skymiles, Mileage Plus or AAdvantage.

Honestly, if you are going to lose the status anyway, I’d just stick with Flying blue. At least you will be able to enjoy the earned status for a little while longer. And when getting closer to the Nov 2024 deadline you may be able to find a status match to a *A or OW airline that allows to extend status by another year (assuming you don’t mind switching your flights to United or American).