Just as a thought, if you are not on the latest 1903 version, you can go
here and force the update by clicking on Update Now. As the update essentially installs the OS new then copies across your personal apps and settings, rather than these buried system settings which you can't affect, it might fix the problem. It is similar to doing a reinstall without the apps hassle.
You can check your version by holding down the Windows Key and pressing r [Winkey-r] then typing Winver in the box and pressing enter. The dialog, next to version, will show the version number. I'm working through forcing my machines to update. It seems that if you are not in the country of the OS settings (I'm UK but my machines live in France), it does not automatically offer the update.
When you are doing the upgrade, ensure that keep settings, personal files and apps is selected.
If you are already on 1903, I think you can use the download tool option and use it to do the refresh. Again you need to select to keep both apps and files.
I don't know if you are signed in using an email address or a local account. I use a local account as I found windows was making it very difficult for me to use multiple skype and onedrive accounts. So I'm not sure what backup and restore options you get for your login.
If you can do the refresh upgrade, I think it's worth doing. It is a lot easier than trying to fix whatever windows broke in the system settings but you do need to ensure it says settings, files AND Apps, or you are left with reinstalling all the apps and doing the register all over again.
Worth a try in this case I'd say.
If you really hate the W10 start bar (as I do), you can create your own shortcuts. This is something I do. I create a folder on my desktop (I call it more icons), then I add that as a new toolbar.
It is easy to create, right click on the desktop, click new and folder. Give it a name.
To add to the toolbar, right click on the toolbar, select toolbars and then New Toolbar. Click on your desktop and select the new folder you made. Make sure, in the Folder box, at the bottom the name is displayed. Don't open the folder as it won't work.
Click on select folder and you will find a new toolbar section at the end of your toolbar (right hand end). You can then open the folder on the desktop and drag stuff from the start menu, once you have it fixed of course.