How can i get the formatting to look as it did before the update?
Before update:
After update:
Conor from Metabase here. You can update column widths by dragging column headers on the question itself (not dashcard) and saving it.
As of Metabase v54, table dashcards apply the same column widths as the underlying question so you can configure them however you want, as long as you edit and save the question first, and then head back to the dashboard.
I am editing the question, but I don't see how i could tell it I want each of the two columns to be 50% wide.
There's no way currently to configure columns as a percentage of the card size. You have to tweak it by hand for now.