focus stacking in lightroom, is it gone?

Focus stacking isn't "gone", it was never there in any version of Lightroom. However, focus stacking is possible from Lightroom too, but requires more work. You can send the images to Photoshop one by one, and then create a new document with the images as layers (that is an option in Photoshop, you do not have to do that manually). After that, it is the same as in Lightroom Classic, but you will have to import the result in Lightroom yourself because it is a new image.