Deductions & credits

@AmyC   DESPERATE for an expert to opine on following.  Im clear that NY allows home office deduction.  I was forced to work at home becuase of covid and set up a roon (about 1/4 of the apartment I rent) as a home office.  The main expense Id love to deduct is a share of the rent (total rent $6000 per month) so that could be very valuable as a deduction.  Is one allowed to deduct that share of rent even though prior to covid that room was used as a spare room and the rent was paid of course anyway.  ie does the expense have to be incremental caused by working at home (eg more electricity or heating use) .  I see nothing written on this  Please advise