I'm a fan of DxO but not an "expert." I export from LR Classic to DxO (using it as a plugin), because I like DxOs noise reduction, perspective correction (it gives me undistorted wide aspect ratio images from my inexpensive EF-S 10-17 lens, turning it into an "anamorphic" widescreen lens, instead of a distorted mess), and it gives me great looking color and contrast without extensive fiddling with curves and such. I haven't had the time to experiment with the features added in the transition from "OpticsPro" to "PhotoLab", but their email support (which is reasonably prompt) helped me move a few tweaks I had made by copying one file to the new program's folder.
To keep the benefits of DxO's adjustments, particularly to color and contrast, I export back to LR as a TIFF, since if I send it back as a DNG I lose those and am back to Adobe's rendition. The export has ".dxo" added into the filename before the filetype extension.
If you're someone who, like me, coming from Bridge and Photoshop to Lightroom, finds the whole "catalog" process off-putting and has never, several years into using Lightroom, put in the time to learn how to use collections and virtual versions of the same image - DxO's import from disk is much more like using Bridge. At this point, I only use Lightroom and Photoshop for layer work or final export to jpg or printing.