Before I became a believer, I used to give Christians a hard time with the “Oh, you believe in three gods” line... but I realized in the end, that it wasn’t that over-simplifiable.
“One God comprising three persons” is the official Christian theology. And this even ends up being respected in a different context by observant Jews, namely that of what gentiles can be validly viewed as non-polytheists and thus eligible to perform certain services for observant Jews. This concept of God is likened to that of a wheel with three spokes, which remains one wheel.