If the installation error message is about a file named "wyserver.wys", the problem is the Windows User Account name. If your Windows User files are located in a folder named, for example, "C:\Users\John Doe\..." (with a blank space between John and Doe) you need to create a new Windows User Account with Admin privileges and a name that does not contain a blank space, e.g., "John". Use the new account to install or update Quicken. Afterwards return to using your regular Windows User Account for running Quicken and doing all other work, as usual.
If the user name is not the cause, try to enable and use the hidden Administrator account. See https://www.howtogeek.com/howto/windows-vista/enable-the-hidden-administrator-account-on-windows-vista/ how to do that. Supposed to work in all Windows versions.
At your next migration to a new Windows version I recommend changing the username to remove the blank space. It's a holdover from old Windows versions using the obsolete "Documents and Settings" folder structure.
If you haven't done so already, I'd say it's time to call Quicken Support on the phone and request help. Let them do a screen share session with you to review the situation on your computer, to determine the nature of the problem and to figure out how to fix it.
Quicken Support: