This is super interesting! Sorry, maybe this is a stupid question, but hope you're willing to clarify. You're saying:
"Later I bought an expired domain related to my niche and wrote 5 to 6 posts related to my niche. I leave it for 1 week for indexing naturally. after that, I create a post having interlink of all those 5, 6 posts and 301 it to that parasite. "
So the 5-6 posts are on the expired domain now. Then you created a post in which you interlink to all of those. You put that on the expired domain as well, right?
Then you 301'd it to the parasite.
If I understand this correctly: you wrote a post on the expired domain, linked to other articles (on the same website), waited until google indexed that single blog post, and then 301'd it to your parasite?
Thanks!