Problems creating a table (or something equivalent)

The table must look like a table both on phone and PC, and cannot be downloaded.

I’m playing around with Anvil just to learn what it can do, and I started with remaking this old site based on Google sheets.

If I start using anvil seriously, I will need to make many large tables, but this first attempt is very disappointing. It looks ugly, it’s difficult to design (drag and drop starts having problems after 12 labels) and I wasn’t able to make a variable number of columns.

I thought about using the borders, but I don’t have the control of which border to show. I want alternating border thicknesses like on the first snapshot, one thick and one thin.