"Your dev kit looks very similar to Inhaos Mega core"
Except mine will plug into a solderless breadboard if you want to.
Have you seen the $10.88 Mega 2560 boards?
https://www.amazon.com/SongHe-ATMEGA2560-16AU-Pinheaders-Compatible-Mega2560/dp/B07TGF9VMQ/ref=sr_1_13?
I can't even buy a chip for that little.
You'd have to buy 1500 chips to get down to $9.95/chip, which I am certainly Not going to do!
https://www.digikey.com/product-detail/en/microchip-technology/ATMEGA2560-16AUR/ATMEGA2560-16AURTR-ND/2357022
