How to remove save and reset button from edit form?

Add this in the method you mentioned

$this->_removeButton('save');
$this->_removeButton('delete');
$this->_removeButton('reset');

Note that Magento does not want you to override the __construct method. You should override the _construct method instead. One problem is that you cannot remove buttons in the _construct method. But you can simply override the _prepareLayout method for that purpose:

protected function _prepareLayout()
{
    $this->_removeButton('save');
    $this->_removeButton('delete');
    $this->_removeButton('reset');

    return parent::_prepareLayout();
}

To remove buttons on MAGENTO 2 admin form:

$this->buttonList->remove('delete');
$this->buttonList->remove('save');
$this->buttonList->remove('reset');
$this->buttonList->remove('back');