Albums in Apples' Vision Pro - how do I get them if I use Classic?

AFAIK (I also don't have a Vision Pro), the Lightroom app works on a Vision Pro, just like it does on an iPad. That means you can indeed sync Lightroom Classic collections and Lightroom on Vision Pro albums, but you have to enable this in Lightroom Classic. Adding a collection in Lightroom Classic does not automatically sync it. You have to sync the Lightroom Classic catalog (as you probably already did), but also each collection you want to sync. 
https://creativecloud.adobe.com/cc/learn/lightroom-classic/web/sync-photos-lightroom-mobile

I don’t have a Vision Pro, but if it works like any other current Apple device (Mac, iPhone, iPad, AppleTV), the central photo organizer for that device is the Apple Photos app. The online Apple Vision Pro help seems to confirm that Vision Pro does indeed use the Apple Photos app, like any other Apple device does.

But, Apple Photos has no directly synced connection with Lightroom Classic, Lightroom, or any other Adobe apps.

(Apple Photos has an albums feature which, yes, works similarly to Albums in Lightroom or Collections in Lightroom Classic, but is not connected in any way to them.)

Because there is no direct connection between any Adobe photo service to Apple Photos, you must export copies of images from the Adobe app (for example, JPEG format copies) and then have Apple Photos import those copies.

Again, without a Vision Pro I can’t confirm this, but one way this might be streamlined is if iCloud Photos is turned on (not to be confused with iCloud Drive). If it is, then Apple Photos is cloud-synced across all your Apple devices, so any change made on one device happens to all devices. The way this might help is, you can set up the album (export from Lightroom Classic and import into Apple Photos) on whatever your most convenient Apple device is (iPhone, iPad, or in your case, the Mac you run Lightroom Classic on) and if iCloud Photos is turned on, that album will sync to Apple Photos on all your other Apple devices. Which means, it is also going to sync to Apple Photos on your Vision Pro. So you set them up on another Apple device with iCloud Photos on, and that album should just show up on the Vision Pro.

The Apple help article Set up and use iCloud Photos does mention Vision Pro, so it looks like this method should work.

Another approach: I saw a video where someone was using the iPad version of Lightroom in their Vision Pro. (This is possible because Vision Pro can run iPad apps.) So if you enabled cloud sync for a collection in Lightroom Classic, that gets synced to Lightroom photos in the cloud, so that would show up as an Album in Lightroom for iPad, which you can run in visionOS. What I do not know is if the Lightroom iPad on a Vision Pro can present photos in the same immersive way as Apple Photos.