If a gynecologist orders a $8,000 dentist drill that probably isn't gong to fly as a business expense. The XDR is a high priced , narrow tool for a narrow market. "I needed a monitor for my headless computer" isn't going to pass any seriously real IRS audit.
The larger the sum heaped on a "tax shelter" business the more likely it will get audited and fail the audit. There are lots of things folks do that won't survive real scrutiny but the IRS doesn't chase down everything.
Well he's writing off a $12,000 computer and $80,000 Tesla for business expenses. Monitor doesn't sound that crazy at that point.