GSA SER can indeed be used for all tiers, depending on what you input. If you feed it with nice, decent content, maintain a good anchor text ratio, and provide good targets from decent engines, it can even be used for money sites.
However, you'll need some money to spend, at least $40 a month to get started for a link list (you can grab a cheap link list with fewer good targets like BuyGSAlinklist, SERPowerList), and 10 proxies .(Reproxy.network ipv4 proxies sre cheap make sure its ip4) You can start with 50 threads to avoid download failures. Many say one proxy is enough for 10 threads, but it's wise to go slow to avoid download failures, as many use shared proxies, and they limit their threads to lower their bandwidth, so less is more.
It's wise to use the same resources your link providers use. I wouldn't suggest scraping yourself, as you need millions of links to scrape and could end up spending a lot of money with very low success, especially if you're just starting.
Last but not least, use a good content generator to arrange good content with nice images, bullets, videos, etc. This can be easily done with GSA Content Generator or SEO Content Machine. Download a trial and download all the content you need, then you can use it later.
Indexing is very important, as Google only counts those indexed. You can use an indexer or multiple tiers. I've seen faster improvements on indexing and positive rankings than it used to be, which is great. If you're on a budget, there are many things you can do, like trying Speedy Indexer to get indexed, which works great with Google. But other search engines don't work as well with that, and you can target others with tiered links. TheBestLink Indexer is also fine, I guess. I haven't used it for a long time, but I believe it's great too.
If you have a few more bucks, try combining GSA SER with Ranker X, which works great. However, don't waste money on GSA SER's Web 2.0s addon SERLib, as it's laggy and not worth it. Ranker X is much better than this.
No matter what, use it with a recaptcha solver like XEvil standalone.