Home office deduction for Major Septic System repair required immediately before home sale

I have been working out of my home exclusively for the past 10+ years.   Before we could sell our home in May of 2020, the county required we perform a MAJOR ($44K) overhaul of our septic System.  

Regarding repair expenses for the entire home the On demand Tax guidelines of TurboTax for Home and Business says "More extensive work, such as remodeling or adding a new roof, should be added in the Assets section as a home improvement and depreciated (written off over several years)."  

Given we didn't have the opportunity to write this off over many years - do I have any options to write off this major expense?