Slicer Settings work fine, at least for me, both Material and Quality.
When you open the Setting to edit them, you can click on 'Duplicate' to make another copy of the settings.
To change the name can be a bit tricky.... Click the Pencil Icon next to the name, then change the name, and click out of the box (Anywhere except the save button... This is key, otherwise it may not change the name), Then click the save button.
All of the other settings you change will automatically be saved.
4 Things to note...
When looking at your selected settings. First, any setting you change in either Quality or Material can be anywhere in the Slice Settings.
A Yellow Line on the left of the setting means it is set in the Quality settings, Orange is the Material, and Blue is Manual/Override User setting.
Also note, Manual User settings will often Stick with that selection of Quality Settings so make sure you check your settings if you have manually changed stuff.
So for your issues, I would say check to see what color the setting is coming from and edit appropriately.
The Export Settings option exports the Quality and Material Settings. If it exports printer settings anywhere I have not seen a way to import them. And it will only import a single setting at a time, at least with the version(s) I am using. I have not checked the latest.
A Side note with the Settings. If you are connected to the Cloud with MC/Matterhackers the cloud automatically saves all of your settings, Printer, Quality and Materials.