Lightroom 9.3.1 - Exporting takes forever & stuck on "preparing"

LR 9.3.1 on Mac OS 26.4.1 with an M4 Pro chip and at least 200gb of free memory. so why, after the recent LR update, does it take the $240/yr app 19 minutes to export 16 pictures? 

it took five minutes to go from “preparing….” to actual exporting. I used to be able to export 30+ pictures in about 30 seconds - pictures i take with a 46MP camera. 

is it because Lightroom is using almost all of the 24gb of RAM i have? 

i try this with full graphics acceleration enabled (use GPU for Export) and without (not using GPU for export). it makes no difference. 

so i ask you, why is my perfectly functional hardware and updated software suddenly incapable of doing anything quickly?