In that case, can you please try this possible fix here:
Looking into Pinch to zoom (not a feature that I use) seems a lesson in disappointment.
Not much support for it on Linux systems. Toward the end of the thread, a user links to a github project on this; I have never tested this:
https://www.reddit.com/r/Ubuntu/comments/hy5zen/pinch_to_zoom_using_chrome_or_other_browsers_in/