Parsing Heavily Nested JSON file - new to Power Query/M - help please?

Yes, you basically wandered into the wrong path.  This here will give you all the records under "other"

let
    Source = Json.Document(File.Contents("C:\Users\xxx\Downloads\TestData.json")),
    #"Converted to Table" = Table.FromRecords({Source}),
    #"Expanded data" = Table.ExpandRecordColumn(#"Converted to Table", "data", {"systems"}, {"data.systems"}),
    #"Expanded data.systems1" = Table.ExpandRecordColumn(#"Expanded data", "data.systems", {"other_waste_tracking"}){0}[other_waste_tracking][systems]
in
    #"Expanded data.systems1"

if you wanted to combine them with the other system then you would need to indicate how you want to do that as one of them has "print_history" and the others have "waste_history"