Steps to reproduce the issue

reproduce:
insert a row where DateTime column is '0' -> in this case insertion does not fail and a new row is inserted
update a row where DateTime column is '0' -> an error is provided from mysql (Incorrect datetime value: '0' for column... )

Expected result

1. either both should fail
2. or none should fail

there seems to be a code inconsitancy in Joomla 4 database drivers as insertObject ignores some of the columns with code:
\libraries\vendor\joomla\database\src\Mysql\MysqlDriver.php

foreach (get_object_vars($object) as $k => $v)
		{
			// Skip columns that don't exist in the table.
			if (!array_key_exists($k, $tableColumns))
			{
				continue;
			}

			// Only process non-null scalars.
			if (\is_array($v) || \is_object($v) || $v === null)
			{
				continue;
			}

			// Ignore any internal fields.
			if ($k[0] === '_')
			{
				continue;
			}

			// Ignore null datetime fields.
			if ($tableColumns[$k] === 'datetime' && empty($v))
			{
				continue;
			}

			// Ignore null integer fields.
			if (stristr($tableColumns[$k], 'int') !== false && $v === '')
			{
				continue;
			}

			// Prepare and sanitize the fields and values for the database query.
			$fields[] = $this->quoteName($k);
			$values[] = $this->quote($v);
		}

while updateObject does not use same logic as above:
\libraries\vendor\joomla\database\src\DatabaseDriver.php

foreach (get_object_vars($object) as $k => $v)
		{
			// Skip columns that don't exist in the table.
			if (!\array_key_exists($k, $tableColumns))
			{
				continue;
			}

			// Only process scalars that are not internal fields.
			if (\is_array($v) || \is_object($v) || $k[0] === '_')
			{
				continue;
			}

			// Set the primary key to the WHERE clause instead of a field to update.
			if (\in_array($k, $key, true))
			{
				$where[] = $this->quoteName($k) . ($v === null ? ' IS NULL' : ' = ' . $this->quote($v));

				continue;
			}

			// Prepare and sanitize the fields and values for the database query.
			if ($v === null)
			{
				// If the value is null and we want to update nulls then set it.
				if ($nulls)
				{
					$val = 'NULL';
				}
				else
				{
					// If the value is null and we do not want to update nulls then ignore this field.
					continue;
				}
			}
			else
			{
				// The field is not null so we prep it for update.
				$val = $this->quote($v);
			}

			// Add the field to be updated.
			$fields[] = $this->quoteName($k) . '=' . $val;
		}

i believe both of them should use same definition on columns which are going to be ignored.

best regards, stan