After many tribulations I have found that my issue with inaccuracies was due to the center of rotation pivot being at 0.5, 0.5 which would move the widget out of its desired position when getting angled.
I kept the pivot at 0.5, 0.5 and made my widgets alignment at 0.5, 0.5 as well as my anchors at 0.5, 0.5. This ensures that all my positions are computed compared to the center of the center of the widget and not the top left.
Of note is the fact that my widgets have to be in a canvas, and that canvas has to be of size 0,0 in my HUD, otherwise I get small positional inaccuracies.
I’m leaving two screenshots of the blueprints for my card widget setup and the change of basis.
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