Like how you Categorize as either ‘Stock purchase/sale’ and Group under ‘investments’.
However, for Type I treat these transactions as Transfers as its not really an expense when you buy stock, nor is it income when you sale stock. Rather its a transfer of cash to stock when you buy, and from stock to cash when you sale.
Agree about brokerage tools for cost basis, capital gains reporting as well. Would take me much longer to set up/track in Tiller than login to Vanguard, retrieve the info and input into a spreadsheet. This is my 2 cents.