Lots of search terms

Hi,

So I have a video game website.
Ahrefs: Domain Rating 3.1 Backlinks 275 (57% Do follow) Referring Domains 114 (57% do follow)
Moz: Domain Authority 4. Linking Root Domains 10. Ranking Keywords: 1.7k Spam Score 9%.

There is a main search term and then there are a large (100+) numbers of terms.

Main search term is 2 words and I have rank #9 on google. It's 5k search volume per month. (with slight variants 20k search volume per month)

Then there are another 100+ terms which are all 2 words each has search volume 8k to 28k. All sharing a word in common with each other.
I'm anywhere from rank 16 to 100+ for these. Ten of them are about rank 20.

I've done all the white hat optimization I can do. The pages even pass google pagespeed with flying colours.
I've got 1 page per search term, with the search term and the url being the same, in title, in header, unique content, etc.

Obviously, I need to get those secondary search terms from page 2 to page 1 on google.
If I'm to go PBN on this, do I do a scatter shot of search terms over the site?
Alternatively, I could focus everything on the main page.

I'm just looking for advice on the best way to go about this.

114 RD and 3.1 DR is really bad. This means that every single domain you have linked is weak, not worth a single second of your time.
Stop linkbuilding that way. It's a waste of time. Learn other linkbuilding strategies, PBN, blasting or maybe if you have some good funds, check for guest posts or build your own microsites
With that numbers, I'm pretty confident that there is plenty of improvement in that site away from on-page exclusively.

Well I haven't linked any domains, it's natural backlinks.
But the main problem is indeed my backlinks are screwed. Good to know.

Sounds like your doing, not too bad... how old is the site?

9 months

well, that really depends on the keywords,
ideally, you should optimise a single article for 3-5 keywords that can be covered in the same topic
If your homepage is ranking for most of these keywords, you can try to include more of them in the content & use good links with exact match anchors for each of these keywords +-, which depends on the keywords competition as well

You can assume the keywords are the names of pokemon. (They aren't but it's close enough)