simple slideshow?

"I just never thought of a regular slideshow as video.."   

Lightroom Classic's Slideshow module output is a MP4 video file.  Even the slideshow programs like ProShow Gold, produce video files.  It makes them easy to show and share.

"Is there a way to add a title slide and/or slides that have only text?"

Yes, there is a wide variety of ways to do that.  Perhaps this will help:  https://helpx.adobe.com/premiere-elements/using/creating-trimming-titles.html

If you are brand new to video editing, you might save yourself some frustration by watching this eight part series:https://www.youtube.com/watch?v=NG18DktkToI

You do have the option.  But, unlike previous Premiere Elements versions, it appears you have to set it up yourself.    

Find the file "PremiereElementsEditor.exe", right click on it and make a "shortcut" for your computer.   On my computer that file is in this folder:  "C:\Program Files\Adobe\Adobe Premiere Elements 2020".  It is a crowded folder, but the .exe is in there!

Are you using Organizer?  If so, skip it and start a new project in Premiere Elements.  I use Expert mode.  Load you images in the Add Media routine and then slide them to the timeline.  When you are done Export it as a shareable MP4 file.  There is more about default transitions and defalut durations, but that is the basics.  It works very well for me.