I'm not sure how much this will help but there's too much detail in what I'm writing to put in a comment.
If the problem is your mouse left button behaves like a right button and you can't move the mouse when you click in order to change that, here are some keyboard tips that might help - I've just played around to see if I can change settings without using the left mouse button:
Right-click (ie left in your case) in the settings area and it opens up the menu then arrow keys let you move up / down through the options, enter to select - you should hopefully be able to open setting with this.
If you then can't navigate to the mouse / touchpad options because the cursor won't move, using arrow keys and tab (to go down / right) / shift-tab (to go up / left) you can navigate to the search icon at the top left (when it's highlighted with an orange box, hit enter to open the search bar). If you then type Mouse and hit enter, it will open up the relevant menu. You can tab to get in to the right hand side of the window and repeat tab until the primary button is highlighted as 'left' then hit space or enter to select it.
I'm not sure if this is the problem you're facing but it's worth looking there. It may well be that the problem is more of a driver issue if you've just upgraded, but this is a simple thing to check first. If it's more complicated, take a look at How to troubleshoot a trackpad/touchpad? to see if it helps. Good luck!
