Keep Calm, (Install KoReader) and Carry On.
tried it and returned to original reader, it was more inconvenient than built-in reader, I liked the idea but it had too many issues
It definitely has a learning curve and took me about 3 hours to get perfect. I’m glad I went through that because I absolutely will never go back.
Consistent fonts, padding, margins etc for every single book is so much better. OPDS support means effortless side loading of books. I love it