Changes

In this case using <tt>deeptextcommand</tt> is the correct solution for capitalizing headers. (Using <cmd>uppercase</cmd> works in this specific case, but only if you stick to Latin 1 or Anglo-Saxon characters. Other languages will suffer from lowercase accented characters, like CAFé.)

Using <cmd>\setuppagenumbering[alternative=doublesided]</cmd> makes the chapters start on the right page. However, the blank page is not truely empty, it contains headers and footers. To get truely empty pages, use the following