I do it in Resolve too. Import the video by clicking create bins. This will create a folder for each video. Then you have to right click on each folder and select "sync audio" (or ....something). This will also take a bit of time but it works. You can even try to import all the video in the same master folder and then do the right click... it works if they are not too many, but with 500 clips i'm pretty sure there will be some mess in there..