I asked myself the same thing and I'm afraid the effect is not as big as expected (in relation to other emissions).

From https://www.agora-verkehrswende.de/veroeffentlichungen/wende... For Germany:

The climate effects of home office were estimated for 40 percent of the workers, each with two home office days per week, were estimated to save 5.4 million metric tons of CO2 equivalent per year.

This corresponds to 18 percent of percent of the emissions from commuting to work or 4 percent of the of total passenger transport emissions (Büttner and Breitkreuz 2020).