You should actually first read the review about
Kobo ereaders and Calibre ebook software 🖱️
Or maybe you are or have been using them already,
then you will understand (recognize) this review even better.
After two years of software-shit and hardware-failures I was done.
And so was my wallet.
Alternative : the ReadEra app
I have installed the ReadEra app at my 5.5 inch android phone and then at my 6.5 inch android phone
to see if I would like it to read ebooks with.
And I do, for 3+ year already.
ReadEra is very easy to setupand it just
uses your directories exactly the same way you copied theminto your phone.
Without surprises ...
One more sign Kobo and Calibre make your live so difficult !