Increase the website's DA gradually. Don't try any quick fixes as they may harm your site. Improve your site's overall authority. Don't rely on third-party metrics. You should acquire backlinks from high-quality niche-relevant blogs with real organic traffic. Drive more link juice to your website. This will help in gaining authority over time.
why do you care? for ranking purpose? if so, then DA means nothing
Probably OP wants to build a PBN to trap noobs by showing High DADA is essentially a pointless metric anymore. It can be manipulated and Moz should probably rework it. It’s a metric only truly recognized by Moz.
Google doesn’t recognize it as a contributing ranking factor.
If you don’t care about your website, I have seen a lot of DA boosting gigs on Fiverr.
How quickly you are looking for?