I used to find it easy to add a new chart, select its type, select data etc etc but Excel 365 has defeated me

What I want is a boring old column chart, with the columns touching each other, just like the column picture when I select chart type.

I insert the chart, select the type (column), select the data and the horizontal axis values (they're dates) and the chart appears.

However the columns are near zero width and I can't find how to make them wider.

Somehow I managed to create a bizarre version where each column is a different colour. They're wider, but the whole thing is a mess.

I went into chart type and found that Excel didn't create the Column chart I had selected but something it calls Combo.

If I change the chart type to Column, I get about thee big columns (there are about 50 data points) and the horizontal axis labels change from dates to a meaningless jumble of pairs of numbers.

How do I create a simple column chart, please ?

PS I can work aroud this by taking an old chart, created in an earlier version of Excel, and copying/pasting it and updating the data source etc, but surely there's a sensible way to create something simple ?