First of all - welcome to BC !
I would agree that the AutoCad welcome screen is a little small but the other three are perfectly legible. Also they merely confirm that something is happening that you expected to be happening, such as opening MS Office. For the AutoCad one you may find an option in whatever they call it - settings, options, preferences, etc. - to change the size of this screen.
With regard to your taskbar icons, you appear to be using the 'Small' icon setting. If you RIGHT click on a blank space on the bar then select 'Properties' from the pop-up menu you will find 'Small icons' ticked, untick this. As this deepens your taskbar and makes all the icons bigger I suggest that you also apply the 'Auto hide' option. This makes the taskbar disappear until you take the cursor down to it when it pops up again. I have a 24 inch monitor attached to this computer and I grudge the space the taskbar takes up ! It's been 'Auto hide' ever since i discovered it years ago, and the smaller the screen I am working on the more I grudge the loss of work space.