Nope you're a mile wrong.
Firstly the link refers to the use of a PPR in the running of one's business. The OP specifically mentions "WFH since before lockdown period" which is something totally different.
More importantly, PPR exemption is only lost or compromised if a home or part thereof is used exclusively for business use for a period.
In the context of a standard PPR, that is a difficult condition to breach.
One particular textbook uses an example of a doctor's surgery attached to a private home, where the doctor allows his children to study in his consulting room, in which case it forms part of his PPR and is thus entitled to exemption.
It also mentions that there is a waiting room, the only users of which are the patients who wait to see the doctor. As there is no personal use or enjoyment of this space, it doesn't form part of the PPR and the value of that room relative to the value of the entire property will not qualify for PPR exemption.
In the real world, a wiser doctor will preserve their PPR exemption by ensuring that they or their family derive some personal use and enjoyment from that waiting room.
A less wise doctor will take at face value simplistic summaries on the Revenue website and not bother availing of a valuable exemption which they could easily have used by taking a few simple steps.
I'm still smiling.