Linking out to websites helps SEO
It has been in my experience that linking out to websites that are relevant to your subject material helps your website rank better for them keywords. I think it’s because citing another website on the subject matter makes your website more relevant to that subject. Google’s official stance is that it doesn’t but it clearly does from testing and significantly too. I think if Google was to make it public people would start overdoing and spamming the process. Google’s algorithm has got incredibly complicated to rank for. I think it has become more focused around links and user queries feedback over bing that is relatively easy to understand how that works and what techniques work well for it.
Here is a site that confirms my findings: https://www.webfx.com/internet-marketing/do-outbound-links-affect-seo.html