Cannot figure out how to create bar chart with line overlay using 3 variables

Your sample did not include any of your attempts, so I don't know what you tried. Here's what I did.

1) In order to have both years filter together, I moved the 2018 data from below the 2019 table up to the right of the 2019 table (columns O:AB)
2) I selected the 2018 data and inserted a clustered column chart.
3) I added each of the 2019 rows as an additional data series, then changed the chart type of that series to line.
At this point, I have a messy chart with 2018 data as columns and the 2019 data as lines. In order to filter the data, I checked the "hidden and empty cell" setting (in the Select data dialog) to make sure it was set to the default "do not show data in hidden cells", then I set up an autofilter on the overall table. https://www.wikihow.com/Use-AutoFilter-in-MS-Excel With the autofilter in place, I select the dropdown next to above pack size and select the pack size(s) I want to see in the chart.