DA is a metric invented by MOZ and google doesn't care about it (you can oftentimes see websites with 0 DA ranking, so this shows you that DA - the metric itself - is not important).
What is important, however is the authority of a website which - coincidentally - coincides with DA (if you can follow me), which is why sometimes it feels like DA is important.
This being said, you will eventually need domain authority (ranking power), and when you have it your DA and PA will increase automatically, and this will help you rank better and for more keywords (that you wouldn't otherwise target). So, the authority of a website is very important, but the DA itself (the metric invented by MOZ) is not important, even though these 2 coincide with each other most of the time (sorry that I don't know how to explain any better)
start with links that cost money, that are hard to get by most people, or both.
If you can't afford to pay for good links you can try with web 2.0s, profile links, quality forum and UGC links (Reddit, Quora, Pinterest, StackOverflow, etc), or quality .edu / gov links
These 4 categories are still safe to use, albeit not all of them will help you rank. But until you make money to afford quality PBNs, quality guest posts, and quality niche edits (which are 3 of the most powerful backlinks today), you can work with the other options. Just focus on pointing them to pages that target easy keywords (usually long tail keywords) so that you have a chance to rank, otherwise I don't think you can push pages like the homepage, for example, into top 10 (even top 20 if you're in a tough niche) with web 2.0s and profile links (the specialty forums and quality edu./ gov links might work, though but again, it depends on your niche + keywords, as well as how well your site is, and how good your content is)
Here's a newbie-friendly guide to educate you on how to approach link building, give it a read as it's important:
This is an evergreen question about backlink velocity that is being asked a lot but even more recently so I decided to share my two cents on it.
I've seen too many starting websites or local business going through the roof with PBN links and getting opposite effect of what they wanted.
First thing I am going to say is that there are no fixed numbers. Sometimes you get away with being super aggressive while other times you trigger a flag for much less. (link sources play a big part of course)
Ideal link velocity is effective and safe. (I do mention risky approaches as...