Exporting 60k photos from Lightroom CC painfully slow. Any tips?

I am moving about 60k photos from Lightroom CC to Apple Photos and the slow speed is killing me. At first I was able to export a couple thousand photos at a time by leaving the computer running overnight, but lately it's been freezing up if I do large quantities.

So now I am exporting about 500 photos at a time, which takes roughly 20 min or so. I have about 45k photos left so I'm going to be dead before this is done.

I'm on a Macbook Air with 8GB RAM and I'm exporting to an SD card with 80GB free. I've also tried exporting to my internal SSD hard drive but I ran into space issues, maybe because of the cache LR has to create when it renders photos.

Here are my export settings: JPG, full size, 80% quality. File naming original, no sharpening, sRGB color space. All metadata. I think it would be faster if I export originals but then I am exporting unedited photos - I want keywords and photo edits.

I tried downloading a trial of Lightroom Classic (which I haven't used in a couple years) to see if I could open my LR CC catalog hoping exports would be faster using that app, but I couldn't open the CC catalog with Classic. There's probably an official way to migrate from CC to Classic. Is that worth pursuing for faster exports?

I don't even know what's slowing this down... is it the software rendering, my machine's speed or RAM, limited hard drive space?

Any ideas on how to expedite this? Thanks in advance!