When Lightroom went creative cloud as a subscription base there was only one version. Later they created a different version for people that wanted to keep images and stuff in the cloud. So they called the original Lightroom Classic. Good choice for having the classic version. I've seen people on trips that don't have a connection to the mothership having issues.
We have been with Lightroom since version 2. It works great as a database for searching and keywording images. Fast to search.
As what was mentioned there are new beneficial features that were added in the last updates. Google these to find out.
If going to Photoshop from Lightroom my gal uses the transfer feature. Right click on image, "Edit in" "open as a smart object in Photoshop"
I see more people using Nix and Topaz while in Photoshop then back to Lightroom
If you are using DXO Photolab here is the method to go from Lightroom.
You can do this from the Lightroom menu by selecting
“File | Plug-in Extras | Transfer to DxO PhotoLab”. This opens PhotoLab and passes the RAW file or files for processing. After applying your adjustments in PhotoLab you can use the “Export to Lightroom” option to send the images back to Lightroom.
It passes to DXO the RAW file without Lightroom converting it or applying edits. So don’t use “Edit In” feature.
Here is a u-tube to show it quickly.
https://www.youtube.com/watch?v=CL0guCUwN7U