Use <table> for tabular data, but for layout you should use grid. Grid doesn't have it's own element like table does, so you have to use css to apply that display to a div.

CSS takes a bit of time to understand. It's cascading nature and how certain properties behave differently based on the html structure or display type or direction makes it tricky. I don't blame you sticking with tables for layouts for yourself - making layouts with floats was a pain. Bootstrap hid a lot of the layout pain. But today we have flex and grid to help us realize our layouts.