I am not with Laminar Research; just a flight simmer from downunder.
If you take the advice I offer you need to be radical and take drastic action.
Saitek software does not work within X-Plane. Your current problem is with the panels but the same drastic action needs to be done with any hardware/controllers you may have.
Firstly you need to acquire some extremely good reliable file/software removal tool/software. Run the software and remove/delete all traces of siatek/logitech software from your PC. When satisfied it is removed find the software and dump all of the discs in the bin. Better still dig a hole and bury it.
Now follow the advice given by Llaslo12704 in his comment above/below and go to this site found at https://forums.x-plane.org/index.php?/files/file/14646-xsaitekpanels-linwinmac3264/ and download the software. However before you download the software you need to "signup" to the site and then login. The prompt is in the top right corner of the screen.
When done, download the software and install. If done correctly and methodically all should work as advised by Llaslo12704. Some additional advice would be to scroll down the page of the above referenced link and read the forum comments ie read everything, as there may be some additional advice from earlier users of the add-on.
By the way, what I see there is no cost involved.
If you are experiencing some minor problem with the Multipanel have a look at the following link found at https://www.youtube.com/watch?v=kQDl-AvREZA from Michael Brown.
Michael runs a business called XForcePC that builds PCs predominantly for X-Plane. Michael's business is supported by Laminar Research as the preferred PC supplier in the USA.
Now, if you are using Saitek/Logitech yoke/pedals/throttles you need to be radical as well and bury the software. These items have to be installed within X-Plane. No other way. Not even through your operating system (Windows?).
Before you make a start have a look at the following link found at https://www.youtube.com/watch?v=hU_TuALAlJk Have a look at the video several times to get an understanding on what needs to be done. Disregard the brand of the controller being installed in the video. It is the principal shown in the video of what needs to be done for each saitek product
Each hardware item has to be installed separately. This means when one item is installed give it a name and save it. Why? X-Plane 11 now has the ability to configure, say the joystick, for every type of aircraft you fly without having to repeat/perform a reconfiguration for each aircraft when you chose to fly. Exit X-Plane and shut down your PC. Connect the next item and then turn your PC on and run X-Plane. X-Plane should recognise the new hardware item connected. Michael tells you this anyway. If done methodically it will take some time.
You also need to ensure you do not assign a button/lever/switche to two instructions or a single process to two buttons/levers/switches. Easily done.