well, you just did it for your other blog, so it must be working
Where it might not work however is in tough niches and for hard keywords (car insurance, loans, anything finance-related.... a lot of education and medical niches, too... everything that's finance and / or health related is usually hard and content alone is not sufficient to rank)
Anyway, SEO optimized content is needed anyway, so you won't go wrong with it...
I would say authority... both types of authority...
- the DR / DA authority thingy, which is always given by links, the more links you have, and the stronger they are, the higher your authority will be)
- the topical authority (ie. cover the entire niche in great detail, get relevant backlinks from sites in the same niche, etc...)
Also technical SEO and on-site SEO in general is important.
Run a site audit and check for (and fix) wrong / bad / missing redirects, broken links, 404 pages, lack of meta tags, etc... just run the audit using the software you like and follow the tips in the report and you should be good overall! (Don't forget to re-submit your sitemap to GSC after you fix everything)
Last but not least, mobile friendliness and internal linking. In easy niches, a well optimized and topically relevant site with proper internal linking can rank without many backlinks... at least for a while until someone sees you bank hard and starts negative SEO-ing your site (or simply outranking you) to steal your dough
Regarding mobile friendliness I've heard someone say on the forum that now having a mobile version of your site is mandatory for google to even consider indexing your site. As with most things google, this filter probably doesn't apply to big dogs, but for the little guy - if this is true - it becomes paramount IMO, so try to have a mobile version of your site, just in case...
- focus on quality (ie. manual links only... at least for tier 1, the other tiers you can automate, but tier 1 should be manually built / bought links and preferably only strong / good / quality ones)
- don't abuse the anchors
- don't spam / rush / blast your site (this is especially important if your site is fresh, without many backlinks, or both. I know that some people say they blast 100s of links to fresh sites without getting penalized and - while I don't fully dismiss the possibility of this being true - I also think that people who do this usually pump dozens sites a month and throw shit at them until one of them sticks. In other words, some of these people hide crucial parts of the whole truth, which is why I prefer to go slow and steady for fresh sites / sites without backlinks).
Here's a guide on link building that will help you come up with a plan of your own, but generally speaking, focus on quality, patience and consistency and you'll win in the long run (well, until google tanks you out of spite regardless, but until then you probably want to stay safe

)
https://www.blackhatworld.com/seo/guide-how-many-links-per-day-week-or-month-should-i-build.1502403/
I hope you won't take this the wrong way, but reading is one thing, doing is another
Also, google doesn't help us either with the constant updates. I remember a time long ago (14-15 years ago) when hearing that google have released an update was time for celebration as - a lot of times - the sites of little guys like me would get a boost if the content was good (of course, I also targeted easier niches in which there was almost zero SEO competition, only message boards, forums, broken URLs, etc were ranking in those niches so I would get in first, optimize the content a little bit with what was needed at that time and google would reward my site with the next update, so I had reasons to love these updates...)
Nowadays? Google updates = boogyman, whenever you read about a google update coming your butthole puckers, you grab the chair and start looking in panic left and right to see where they hit you from. And sometimes (or, rather, most of the time) these new updates only reward big sites and / or spam sites... anything that increases google's profits, screw the little guys and the content relevance...
Anyway, keep reading (you have to if you wish to stay informed on the latest google updates and what's working now), but also keep doing stuff, too. No action, no results