How to make use of Devel debugging functions on large or complex objects
The first problem can temporarily get fixed by changing the max array/object levels Kint will go deep. Currently this still has to be done by changing one line of code in the module. Though there already is an issue https://www.drupal.org/node/2405179 to make this a configurable setting.

In devel/kint/kint/config.default.php change 7 to any number you are fine with. I usually set it to 4.

/** @var int max array/object levels to go deep, if zero no limits are applied */
$_kintSettings['maxLevels'] = 7;


Remember that this number will get reset as soon as you update the Devel module.



Update: Now I found this beautiful snippet to simply be placed in your settings(.local).php. No hacking or patches needed.

// Change kint maxLevels setting:
include_once(DRUPAL_ROOT . '/modules/contrib/devel/kint/kint/Kint.class.php');
if (class_exists('Kint')) {
  // Set the maxlevels to prevent out-of-memory.
  Kint::$maxLevels = 4;
}