Spherical earth is not any kind of Catholic "teaching". It's an opinion that some Catholics have held, likely due to following Aristotle. Aristotle gave the example of the boat sinking beneath the horizon. Well, neither Aristotle nor those who followed him, had a Nikon P900/P1000 camera or a telescope so they could easily bring the entire boat back into view.
This is a matter of science, and I don't need to follow the scientific opinions of even a St. Thomas Aquinas (whose science caused him to misfire a bit on the Immaculate Conception). There are no theological reasons to believe that the earth is a sphere, and so whatever opinion certain Catholics held about the matter isn't worth much more than that of my next-door neighbor.
There's solid Scriptural support for a physical firmament. There's lot of Scripture which suggests that the earth is flat, although admittedly it could be explained as a bit more figurative. But there's no explaining away the firmament. But that's as far as it goes.
It just seems a bit inconsistent, even hypocritical, to dismiss the opinions of the Church Fathers regarding the Genesis account of creation due to supposed "advancements" in science but then claim it's consistent "Catholic teaching" that the earth is a sphere.
Evidence is mounting that the earth is flat.
Atheistic modern "Science" rejects much of Sacred Scripture, which clearly teaches, for instance, that the earth was made before the sun and the moon, that there were waters above and below the earth, that man was made from the dust of the earth, etc. "Science" rejects all that too ... but we know they're dead wrong.