They look like a sort of mealy bug to me. Spray isopropyl alcohol on them and if they turn red then definitely mealy bugs.
Get a cotton swab, spray it all down with alcohol and wipe them away and that should clear them up! Luckily they are pretty large and easy to see (at least more than other pests).
This sounded great until the part where you can only read the ebooks using their app and you can’t transfer to kobo/kindle. That is a dealbreaker for me unfortunately.