301 redirect vs PBN for new domain?

I've got a few new domains, it seems like 301 redirects are more popular nowadays with less work and effort, however still getting some of that authority in its link juice.

What would be your suggestion on the best way to properly set up a site/domain, and get most of its credibility via it. I'm also looking to use this domain for cold email, so a redirect might be perfect

if the domains are not closely related to the topic / niche of your money site I'd not redirect them, I would use them as PBN instead (or even as money sites)...

301 redirect is safer and easier. But PBN needs more maintenance risk.