Coffee Production does indeed hurt the planet, in fact Brazil, the world’s largest coffee producer, saw deforestation of its Amazon rainforest reach a 15-year high, according to a report published by Brazil’s National Institute for Space Research.

https://www.cnbc.com/2021/12/16/climate-change-lab-grown-coffee-and-sustainable-ways-growing-coffee.html

Deforestation to add coffee trees?

Yup, deforestation can occur on coffee farms to make more room for coffee trees

https://perfectdailygrind.com/2022/06/deforestation-in-coffee-production/

So do coffee trees not make oxygen?

Coffee trees do make oxygen as a byproduct. In fact, a coffee field has the ability to produce half the amount of oxygen a rainforest does occupying the same amount of area.

Overall, coffee production does hurt the planet because it alters rainforest ecosystems which negatively affect plant and animal species living within. But it does produce oxygen but not as much as a rainforest.

http://bioweb.uwlax.edu/bio203/s2009/fitch-br_made/Nutrition.htm
https://ohiostate.pressbooks.pub/sciencebites/chapter/a-bitter-brew-coffee-production-deforestation-soil-erosion-and-water-contamination/

Except most oxygen is produced by microorganisms in the ocean.

Correct, about 50% of the world's oxygen comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize.

About 6% of the oxygen comes from photosynthesis from the Amazon, which means about 5% of the world's oxygen comes from a coffee field. So coffee production hurts the planet more than helps improves the planets despite leaving some oxygen behind.

https://oceanservice.noaa.gov/facts/ocean-oxygen.html
https://www.newsweek.com/how-much-oxygen-amazon-rain-forest-1456274