Hacks Need Font Hack for Kindle Paperwhite BO1D (Fifth Gen) FW 5.6.1.1

[dkc.com]

Totally new here. This is my first post. Need help. I am totally a non-techie guy who can follow instructions only.

I have a Kindle Paperwhite BO1D (Fifth Gen) with FW 5.6.1.1

I am a Gujarati (from Gujarat, India) and the Kindle doesn't render the Gujarati fontસ well. So I jailborke it, installed Kual & KoReader only for that purpose, thanks to a step by step guide from this forum. Now the Gujarati fonts are rendered correctly in KoReader but they look very weird. How can I install the fonts of my choice for only reading books in KoReader? I don't want to change GUI fonts. They are just fine.

I even don't know how to install a package or something similar on Kindle without a step-by-step guide so can anyone point me to the simplest or step-by-step solution?

Thank a lot in advance.