What is the efficient way to process hundreds of images?

The first trick to speed up import, culling and processing is to import using embedded previews which makes Lightroom completely skip the step of generating previews which is useless anyway and just use the already generated (by the camera) jpeg previews. Also make sure to set the raw default for your camera to "camera settings" in Preferences->Presets. Now you import and the previews are there right away. Step through the images and immediately apply Pick (P), and Reject flags (X). Filter the view for just your picks, select all and hit command (control on windows)-N and create a new collection with the picks. Do not create virtual copies, just create the collection and include the selected images (makes sense to do it in a collection set you already set up for the shoot in advance) and name it with your shoot and first cull as name. Then do the same inside that collection and get down to a manageable number through succesful iterations if needed. You might end up with a number of succesively smaller collections. You can give ratings while you go but doing simple thumbs up/thumbs down (pick, reject in Lightroom parlance) is much faster. Ratings are better done when you already drilled down. Then edit the images you have left which is hopefully a much smaller number than you started with. Use syncing for settings changes that are likely global (e.g. white balance, profile, etc.). 

The main trick to speed this process up is to import with embedded previews. This saves enormous amounts of time as you don't need your compiter to do any unnecessary processing of raws you will never even edit. Also delaying going into develop as long as you can will help enormously because you (or your computer) end up again not doing any work that is not needed. Culling in Lightroom Classic is not as fast as photomechanic for sure but with this approach you get pretty close. 

Take a look at the application Photo Mechanic. It's very , very fast for copying your files to the destination folders and simultaneously letting you view and choose the images you want to bring into Lightroom Classic. Depending on your style/type of shooting, it can get thousands of files culled down to a few hundred to import. 

You can also find good videos about it on YT,