DR boost for new site via 301 redirects

I've come across different postings on freelance websites. Freelancers boost your domain DR (or DA, if you check with MOZ) via a bunch of 301 redirects. And they can get your DR pretty high, much higher that you can do with simply buying cheap links. And it works really fast.

So I have two questions about the topic:

1. Is boosting DR with this method actually works? I mean, that it affects your ranks? DR really gets boosted, that's for sure.
2. If the method works, how old must be a website to employ this tactic? If I have a 1-month-old domain and it suddenly gets DR 20 - isn't it suspicious for Google?

1. No
2. Shouldn’t take 3rd party matrix serious, DR is very easy to manipulate

Don't bother with 3rd party metrics when thinking about traffic or rankings.

A service to increase your DA/DR will do exactly that: they will manipulate a 3rd party metric. This doesn't mean Google will suddenly look at your website and decide to reward you with better positions on the SERP, because Google doesn't care about what Moz or Ahrefs scores your website on a 1-100 scale.

Won’t work for long, I would avoid it

I'm kind of thought that these are useless, but thanks anyway. Hope I will see at least some minor improvements from this activity on one of my websites.