Believing that the Earth is flat on the basis of that argument certainly isn't belief on the basis of faith.

Catholics as a group don't "ignore all the counterarguments". So for example, Ed Feser recently published a book presenting five arguments for the existence of God (https://www.amazon.co.uk/Five-Proofs-Existence-Edward-Feser/...). The book responds to the various counterarguments that atheists and agnostics usually make to these arguments. You might not be convinced by the responses, but the counterarguments are not ignored.

Again, I am not trying to argue here that Catholicism can ultimately be rationally justified. I'm not a Catholic, and it's not particularly important to me whether it can or can't be. But it's unfair to caricature Catholics as a group as irrational faith heads (though no doubt some individuals may meet this description).

"Argument: "If earth was flat it would look flat. Earth looks flat therefore it must be flat."

It's no longer faith, it's reason now. Doesn't matter that you ignore all the counterarguments."

Exactly! Otherwise literally everyone on earth could be said to be acting on 'blind faith' because nearly everyone holds at least one or two mistaken beliefs out of some prejudice or unwillingness to examine the counterarguments.