Until at least Manjaro MATE 20.03 the Alt+Tab (windows selection) utility is quite un-intuitive, as it is badly indicated which window is the user choosing.
This happens with the default theme:
The color in the switch-tab is a bluish dark gray, and the selected window's color, a grayish dark blue.
Actual view, low-contrast colors.
This would be improved changing the color of the selected window to a lighter one and/or showing a thumbnail/previsualization of the window selected (before releasing Alt+Tab and going to that window)
Proposal for a higher-contrast colors.