Editing in TIFF after RAW

 I assume DPP4 means the Canon raw editing software that comes with the camera. This has no effect on Elements.

After clicking “Open Image” in the camera raw dialog your raw editing is saved e.g. when you save a tiff or jpeg including any further editing e.g. using layers, text etc. in the PSE Editor. If you ever open the raw file again, the slider settings should be remembered.

As I have said, if you make edits in ACR and open the file in the Editor, then save the file to any format, the edits will be saved.

I have no idea what DPP4 is.

To claify, if I start with a RAW file and make the initial edits in Elements 2020 for RAW,  then click "Open Image" or later on open the saved version of the image as TIFF, do I have to then go in and re-do the edits such as levels, brightness, hue/saturation, etc. in the Expert mode after already doing them in the RAW mode.?  Likwise if I use DPP4 and do those initial edits, do they need to be re-done when I open the image in Elements 2020?  Is there any reason to re-do them once they have been made?   Thanks

What do you mean when you say you go to Expert as a TIFF?  If you start off with a raw file and then open the file in the Editor after making your ACR adjustments, you can save the file as a TIFF and all of your adjustments will be saved.  If you open a TIFF file in ACR, make your adjustments, open the file in the Editor and save the file, again all of your adjustments will be saved either to the original TIFF file or to a saved copy.