some puzzle about controler and adapter

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1st:Shall i need to remove the old controler of keyboard to use micro pro as a new one to get it have able to flash my firmware ？

2nd:are there have some keyboard with no cpu?(Controler) ，i mean all i need to do is add a controler to it with diy able .do that right?
3ird:will the old controler be disabled if not remove it just add a new one?

btw : https://deskthority.net/workshop-f7/how-to-use-a-pro-micro-as-a-cheap-controller-converter-like-soarer-s-t8448.html
https://github.com/nathanrosspowell/FC210TP
this is all what i already consult

i have LEOPOLO FC210TP from github we can know that it's confirmed by other people the keyboard can be programable