- the size difference is because KeePass offloads a lot of work to the .Net framework, and in contrast KeePassXC does that same work itself. - I'm not positive

- the size difference is because KeePass offloads a lot of work to the .Net framework, and in contrast KeePassXC does that same work itself. - I'm not positive I'm understanding your question, but KeePassXC takes security just as seriously as the original KeePass does - Yes, you can use KeePass2Android, or any other KeePass compatible software. KeePass and KeePassXC use exactly the same database format