I think PA & DA 30+ is good enough.
One thing to keep in mind when you’re hunting for a badass domain/backlink is DA & PA are both measured on a logarithmic scale. So every single point increase makes a domain 10 times more powerful.
As such, finding domains with DA +30/PA +40 that are clean are incredibly difficult and usually will be fairly expensive to purchase.
The other thing to remember is when you see a PA of 1 and a DA of 22 it doesn’t mean the website is garbage. It means you’re not looking at the most powerful page on the website.
So anything above 15 is good.
Trust flow and citation flow ratio
The ratio between the above two metrics matters a lot in determining the overall trust of the site.
If a site has a citation flow of 40 and trust flow of 20 then the ratio is 2:1 or 0.5. The maximum ratio possible most of the times is 0.9. However, Google is an exception, it has the ratio of 98:99.
Nearing to the ratio of 1 is desirable. Average trust to citation flow ratio should be 0.50. More the authority and trustworthy the site, the ratio is higher.
If the trust flow is greatly lesser than the citation flow, then it is clear that the site is having low-quality large amount of backlinks.