Budget feature in QBO

Hi there, I'm new to QBO and to business. 

I started on 5th March, a week before the world imploded.... I used an excel spreadsheet alongside QBO for March, April & May in order to calculate my stock budget.  I did this by laying out all of my fixed expenses and inputting predicted figures for variables such as daily sales and wage expenses.  On a daily(ish) basis, I'd update with actual sales and wage figures which would then increase or decrease my remaining stock budget.  

Now that my QBO accounts are all up to date and I've made my first VAT return, I'm ready for the next step in ditching excel.  My business is a bricks & mortar retail store and the only 'customer' that we have is 'daily sales'.  Would it be reasonable to use the timesheet feature and bill staff hours against daily sales so that the data pulls through into the budget?  My staff are hourly paid and are coming in fairly erratically at the moment what with COVID.  I've had a play with timesheets and billing against daily sales and it seems like I have to raise an invoice to do it this way.  Would it be a bit odd for me to invoice my own company for staff wages?

My main objective is to be able to use the budget feature to know where I am throughout the month in terms of remaining stock allowances.

I hope someone can help here as I'd really like to have all of my data in one place.  

Many thanks

Jane