Hey! You might be interested in this forum post on suicide hotlines from a while back. https://forum.effectivealtruism.org/posts/Xh5oyGkngGjCmNhcP/how-impactful-is-being-a-suicide-hotline-volunteer
Unfortunately, I think the comments in the post (including one from a former volunteer) make a really compelling case that it takes a lot more than 5 hours to prevent a suicide. I think it takes at least hundreds and probably thousands of hours of calls.
Congratulations!