Sendkeys not working for picker wheel, we also faced the same issue while automating picker wheel, so for that we have used workaround ie tapping on picker wheel element and getting attribute value and findout that value of the picker wheel element is exactly the same that you want to select.
int Balance = 0;
if(direction.equalsIgnoreCase("down")){
Balance=183;
action.tap(test3.getLocation().getX(), test3.getLocation().getY()+Balance).perform();
}
else if(direction.equalsIgnoreCase(“up”)){
Balance=170;
action.tap(304, 600).perform();//use same technique which is using in if loop.
}
String strValue="//XCUIElementTypeOther/XCUIElementTypePickerWheel[1]";
MobileElement Value = (MobileElement) ((AppiumDriver) CL.GetDriver()).findElementByXPath(strValue);
String collectdata=Value.getAttribute("value");
Above code write in function and loop this function until you are getting the required element.