I’ve read the Dhammapada (a central text of Buddhism) several times through. It’s striking how similar the two are - the Buddha actually uses even the same metaphors as Jesus - like the house built on sand.
In Orthodoxy (I am not sure if it’s also in Catholicism), we have this idea of pre-Christian sages who intuited knowledge of God through nature (since God is “everywhere present and fills all things” according to Ephesians), even if they never made contact with Jewish society. St. Justin Martyr called these people “pre-Christ Christians” and named Socrates, Plato, and Aristotle among them. Other saints also name Heraclitus, since he philosophized about the “Logos”. Abbot Damascene (a priest-monk in Alaska) most recently named Lao Tzu, author of the Tao Te Ching in this same category.
About the Buddha, I don’t know of any saints who speak about his ideas, or current theologians. But from reading the Dhammapada at least three times and the 101 Zen Stories ( 101zenstories.com/ ) at least twice, it is clear that the vast majority of our ideas are the same. I would say those stories have helped me on the path to salvation - especially when I nitpick a certain article of our Orthodox Faith and lose the “Spirit” of the law; the Buddhist interpretation helps give me some perspective. I’ve found it helpful but others might not.
Does this strengthen Jesus? I think it does. If there is one overall truth, it’s probable that many different groups have stumbled upon parts of it in different places: Lao Tzu recognized the unspeakable, unfathomable nature of God and expressed it in Taoism (“The Tao that can be talked about is not the eternal Tao”). Buddha recognized so many other things about this Way, like how hatred does not cancel out hatred, or how we all fear harm, so we should not inflict it on others. However, the one thing that our religion has which the others do not is the Incarnation of God (the Logos) in the flesh. The idea that God is three people (the Trinity) in one could only be given to us by God’s revelation, since this mystery is not something that human reason and logic could arrive at.