Upload content consistently. Follow top influencers and try to engage with target users.
Do not follow or like multiple accounts in a short time.
Use the only relevant hashtag. Do not repeat the same hashtag.
You can start building links in the initial month but keep it less and prefer quality links. But, if your post gets viral, you will get organic backlinks + traffic, user engagement and more exposure...
That might be the reason why the new site with many backlinks and doesn't have user...
To get a natural backlink, then you have to upload content that has user intent and is more worthy. So your site value increases organically and backlinks naturally.
You could try quora, and guest post on relevant sites.