Data Visualization Engineer to take an excel spreadsheet in Tableau

We are looking to build a tableau dashboard with a spreadsheet built it out in excel. More details will be provided to candidates. We would also like to have someone to go to for future work. In its current form, the excel model uses tons of nested if statements and other functions that require a ridiculous amount of processing power, so it's too slow for us to play around with changes to the model. We need someone to take the logic and simplify the formulas, but maintain my ability to make changes. Then visualize the output in a clear way so We can easily view the consequences of manipulating the inputs.