I think you should understand what those acronyms mean in their essence:
I understand that RD is referring domains. In this case, referring domains is not a metric that you can just say "20" or "3". Is just a number. The number of domains referring to the give site you are analyizing. Is like saying: "what is better, having 10 candies or having 100 candies"?
It depends on the quality of the candies. Is not the same 10 quality candies at $10 per unit than 100 shitty candies at $0.01 per unit... 10 x $100 = $100 in candies vs 100 x 0.01 = $1... So saying "I have a RD 100" is awkward... because the 100 could be straight $0.01 candies.
There is where other metrics like DA, DR or Majestic's TF are worthy. Theoretically, this are metrics that based on multiple factors, try to measure how worth are those candies. They use parametrical and statistical elements in order to do this calculus, therefore the more the better, but this is not always true.
This is why, you have to look at the linking profile. Metrics like TF are just a filtering method. Some people just say: "Ok, filter me out all domains with TF below 15". So if you have a list of 100.000 domains, you will end with, maybe a couple hundred domain in your list. Then you will say: "filter me out all domains below 20 DA", and you may end with 50 domains in your list. And from there, you start evaluating the linking profile
1. TF= 5 and RD=15
2. TF=25 and RD=2
So if you offer me those two domains I will disregard both
The first has too low TF for me so I will discard it straight away (for example, by filtering everything below TF 10)
The second is weird: 2 RD with TF 25 says that, there is at least a very valuable RD. You must look the domain. And maybe you can check other tools like Ahrefs and Moz, because sometimes, Majestic doesn't find all linking domains and you may see other domains that could improve that TF (which, is unlikely but possible). If still there are 1 or 2 RD in other tools, I may disregard it. Anything below 30 or 40 RD I feel is easily achievable (unless it has plenty of links from newspapers/wikipedia, for some reason).
And be aware that TF could be manipulated through linking hubs. So you could have a big TF if the source of that TF is just linking other TF sites at the same time despite of not being worth at all.
Despite metrics are sold like a marketing tool, be aware that they have to be handled with kid gloves.