Domains with DA 50+ and PA 44+

Hello,

So I purchased 6 domains (3 .info, 2 .net and 1 .com) which were expired.

All of the domains have DA 50 and above and PA at least 44 and around 2 thousand backlinks within 1-15% Spam Ratio (Using Moz Pro has been checked). I wanted to 301 redirect them to my niche sites but they don't seem to do anything at all.

I want to use this six domains as my "backlink" source for some of my CPA Niches. Like for example "Fortnite Generator" or something. Maybe even MaxBounty Offers?

Like let's say I buy a domain "getvbucks.com" (example) and use these 6 already purchased DA 50 domains and link them as "click here to get free vbucks".

My Question is: What is the best way to backlink. Should I use wordpress and do some posts and Put the links below the posts or should I make a black HTML file and just do "ahref" to all my niche links?

If someone can give me some tips on what can I use these websites for would be great as well.

Also, if anyone wants backlinks from any of my 6 websites for free kindly post below and I'll be happy to backlink your websites.
Also, how easy it is to rank them and what to do with these kind of domains?

If these domains aren't spammed to death and beyond, I will eat dry horse crap. Moz Pro is completely useless to check any kind of abuse. You will not find any top TLD domains for free with DA50+ that weren't spammed to Moon and back. I can assure you of that. I wouldn't touch these.

Also, unless these domains are 90%+ related to your money site, don't do 301 redirects. Even anchors get redirected and you will only screw up your site. Not to mention it takes ages for 301 to take effect.