that's the problem! Quality links that can get you rankings cost money, so you have to pay instead of dicking around with free links and wondering why you don't rank.
links that meet most / all of these criteria:
1) come from legit sites (legit sites = sites that google doesn't consider link farms, link farm = site that exists only for the purpose of selling links, you can identify link farms by checking the content of these sites and looking what they're linking out to, if they link out to sites like yours, or to other blogs / content sites that are weak in general, or - worse - to sites that are not even related to the topic of the content then it's clear that the site's a link farm and a link from this site is useless in the long run, might be worth something temporarily but sooner or later google will penalize it)
2) besides not being placed on a link farm, the link also needs to be placed on a site that ranks in google and gets decent traffic (at least few 100s visitors for a few dozens keywords). Ok, I've pulled these numbers out of my ass, it's true! But the point stands: you want your links to be placed on sites that rank in google, just to be extra safe that the site is legit...
3) is d0follow, be the 1st (or 2nd at most) link on the page, and the content where your link is placed into should not be more than 3 clicks away from the homepage (exceptions apply for big sites as big sites with dozens or 100s of categories and sub-categories might place your link 4-5 clicks away from the homepage if the category is obscure).
Now, the maximum 3 clicks away from the homepage part is not as important as the other parts because even if google doesn't have enough crawl budget to crawl the page with your link you can always force-index that page, or build links to it and force google to discover it that way. But it's something to keep in mind if you're really paranoid like I am
4) come from sites that have decent authority and, preferably, they're relevant to your niche. The authority part is self-explanatory: the higher the DR of a site is the more link juice (ranking power) your site usually gets too, so aim for sites that have good authority (DR). I'd say anything over 25 DR is good, but even if you can only find sites with low DR (say 10 or less), it's still OK if the sites are good and in good standings with google, so don't dismiss this option.
The niche relevancy part is also important as you, ideally, want to have backlinks from sites in the same niche as you since it makes sense - for example - for a pet store website to link to a pet food website instead of linking to a soccer-related website. So, getting links from relevant sites in your niche is kind of important.
However, if you can't find lots of sites in your niche that you can get links from (this does happen a lot with small / obscure niches) you can get link from non-relevant sites just fine, just make sure that the content that gives you the link is at least remotely relevant to the topic of your site...
5) are in-content. This one's self-explanatory, too, but in case it's not obvious then know that google favors links that are surrounded by text more than any other links (footer, or sidebar, for example). So, aiming to get as many in-content links as possible (not ONLY in-content links, though, this is another thing to keep in mind) should be your goal.
But like I said, having only in-content links (as powerful as these are) is not recommended because google hates link builders and will do everything they can to catch and penalize them. And one of the methods that google uses to catch link builders is looking for patterns. Nature doesn't usually create (at least not easily recognizable) patterns. humans do. So, when you see a site that only has in-content links, or only links pointing to the homepage, or only links using the same 1-2 anchor texts everywhere... well, these are easily recognizable patterns that tell google "hey, look! Human intervention in this link building process, time to knock this guy off the SERPs" so google penalizes your site.
Moral of the story: get as many in-content link as you can but don't have only in-content links pointing to your site. Have some image links too, PDF links too, links pointing to your social profiles too, also link to other pages too (not just to the homepage), vary the anchor texts a lot, etc... Basically, mix and vary as many elements as you can so you can mimic randomness and hopefully trick google into thinking that your link profile is natural (organic) instead of being built by yourself.
Oh, and also mind the link velocity, too. That's another important part. You said that you've build 900 "quality" links, but if you've built those 900 links in one week I'm not surprised that you're not ranking. New sites that nobody knows about yet (and your site, probably being new so not having any traffic yet) getting 900 links (from what google considers to be 900 other real people's websites) is awfully suspicious, because how did 900 different people give you a backlink when your site hasn't been visited by a single person yet. And if you have any of google's tracking tools installed on your website (GA, GTM, etc) google knows this so it's easy for them to penalize your site.
Not only do I think that the 900 "quality" links are not quality (because they're free and google almost always devalues free stuff that's easy to get), but you might have also screwed your site by blasting it with 900 links in a short period of time. Link building to fresh sites (especially sites that have no traffic yet) should be done slowly and gradually, start with few backlinks a month (1-10), then increase this number as months go by and your site builds up the traffic. When it comes to new sites link building should go hand in hand (and keep up) with the levels of traffic initially. After things look safe and stable you can start blasting if you want, although - if your rankings and traffic level keep increasing month after month due to this slow but gradual link building process - it makes no sense anymore to blast your site and risk losing everything, so I still don't recommend blasts even in those cases
Long reply, I know, but I got triggered
... But hopefully, you understand what I've tried to say and while I might not be correct on all points (have been out of the SEO game for 3 years), most of these points should still apply in today's SEO.
Last but not least, here's a guide on link building that can help you understand how to build links safely:
https://www.blackhatworld.com/seo/guide-how-many-links-per-day-week-or-month-should-i-build.1502403/
