Good device for DIY books, manga, comics?

[biGPlant]

Hello again.

You may recognize me as the guy who bricked his Libra 2 after trying to flash koreader and not correctly following the instructions.
I tried to bring it back to life, but failed.

If I were, in theory, to buy another device for:

• diy books like this one --> Ultimate Guide: Plumbing in PDF format.

• magazines in PDF format.

• manga in cbz format

• comics in cbz format

• basic epubs support

What would be optimal for this?

I promise I won't break it this time

Thanks for reading!