May I ask if locally is Kazakhstan? If so, I would imagine the market for second hand Mini's might not be so strong..
I had previously followed your posts with interest regarding the Mini. I too purchased an i7 mini with egpu, became disappointed with the performance, and have demoted it for a custom built pc (best computing decision I have made for a long time).
Did you become too disappointed in yours to carry on using it?
I suspected the resale price for a second hand mini would not be worth selling it so soon, so it has become a family computer.