The last time someone asked about a pareto chart, I wasn’t able to solve the ordering problem using the query editor. (Metabase has no concept of ordering a window function by its input, it wants the metric and dimension to be separate things.) I’ve linked the thread below.
I ended up using a SQL query so I could control the window function ordering directly. It also avoids the need to create 2 separate questions (one for the bars and one for the cumulative line) and either join the results in a 3rd question or use a dashboard combo chart with the 2 questions as data sources.