With your shown samples, could you please try following rules. This will take anything in REQUEST_URI starting.
RewriteEngine ON
RewriteCond %{QUERY_STRING} ^$
RewriteCond %{THE_REQUEST} /([^/]*)/([^/]*)/([^/]*)/([^/]*)/?\s
RewriteRule ^(.*) /%1?username=%2&profile=%3&data=%4 [NE,L,NC]
OR(either use above or following one) in case you want to match users in URI then run rules then try following.
RewriteEngine ON
RewriteCond %{QUERY_STRING} ^$
RewriteCond %{THE_REQUEST} /users/([^/]*)/([^/]*)/([^/]*)/?\s
RewriteRule ^(.*) /users?username=%1&profile=%2&data=%3 [NE,L,NC]
Explanation: Adding detailed explanation for above.
RewriteEngine ON: Enabling RewriteEngine here to enable mod rule writing.
RewriteCond %{QUERY_STRING} ^$: Checking condition if query string is NULL then go further in rules.
RewriteCond %{THE_REQUEST} /users/([^/]*)/([^/]*)/([^/]*)/?\s: Matching regex in THE_REQUEST from /users to till spaces and capturing 3 groups values into back references to be used later.
RewriteRule ^(.*) /users?username=%1&profile=%2&data=%3 [NE,L,NC]: Using url rewrite to change URI to as per OP's request which has back references values in it.