Now you seem to be torn between Sched A and Business deduction. Your client is an Employee. Deductible as business, no matter what are the components, does not apply to your client's personal taxes, as an Employee.

The Intuit article you linked to has a mix of concepts and is poorly written. The text includes if you are an employee of a C or S Corp, then you can take home office expenses if you file Sched C, is poorly edited. It seems like an older article that has been updated. It has a listing of "expenses" which does not include Depreciation, and it has this statement, "To be clear, this only applies if you claim the home office deduction if you have your own business and use a portion of your home for your business. It is no longer allowed for employees under TCJA." Being the sole shareholder is not the same as "have your own business."

It also covers that the depreciation is not recaptured under the newer limits for exclusion of gain from sale of a personal residence. So, it is what I call a Word Salad.

"part of me thinks that this home office is a different animal and could still work"

What does that mean? It isn't any different than what the tax regulations provide for.