Trent Horn tells us that we should first ask the person what is their source for the accusation. These statements can often be old recycled arguments from non-reliable sources. Asking for the source will get the other person thinking, and it can also give you the opportunity to show proof and evidence supporting Catholic beliefs.
Ask the person what is your primary source to show you these ancient religions predated christianity and believed in these very specific things related to christianity.Trent Horn
Nine times out of ten they can’t give you a citation. They’re just taking it on faith, reading from this anti-catholic or anti-christian author they’re quoting.
It’s not really helpful to tell the other person that they are wrong when they bring up claims against Catholicism, and it is better to ask the question of how they came to believe that or why do they think that is true. Asking for evidence can plant a seed of doubt which can be more effective than just telling them they’re wrong.