$ sed -nr '/Username/{n;s#.*>(.*)<.*#\1#p}' file
wipis_dxu
Brief explanation,
/Username/: find Usernamen: Read the next line of inputs#.*>(.*)<.*#\1#p: extract the string between> ... <
2
solved Grep a word from XML file with grep/sed
$ sed -nr '/Username/{n;s#.*>(.*)<.*#\1#p}' file
wipis_dxu
Brief explanation,
/Username/: find Usernamen: Read the next line of inputs#.*>(.*)<.*#\1#p: extract the string between > ... <2
solved Grep a word from XML file with grep/sed