Are we consuming more oxygen than the world is producing due to fossil fuels?
Yes, atmospheric oxygen is being depleted by fossil fuel burning.
From https://cdiac.ess-dive.lbl.gov/trends/oxygen/modern_records.html -

Oxygen concentrations are currently declining at roughly 19 per meg
per year, or about 4 ppm per year. One &quot;per meg&quot; indicates one
molecule out of 1,000,000 oxygen molecules, or roughly one molecule in
4.8 million molecules of air.

And -


fossil fuel burning is depleting atmospheric oxygen at a rate of almost 1000 tons per second. There are about 32 million seconds in a
year, so that somewhere around 30 billion tons of O2 are being
converted to CO2 annually.


Because the quantities of O2 are very large the reduction is small in comparison. From same source -

There are about 1,200,000 billion metric tons of O2 in the atmosphere,
so we can keep burning fossil fuels at the present rate for 40,000
years before we run out of oxygen. By then, all of the world's fossil
fuel supply will have long since been exhausted.