PHP - Implications Of Entity One-to-one Relationships

I am using API-Platform, Doctrine, and Symfony with entities that utilize class type inheritance to extend an abstract entity.

I've been running into one issue after another primarily related to the serialization process (serialization groups, parent annotations not propagated to the child, etc), and while I am sure user error on my part is part of the culprit, it appears that API-Platform and potentially Symfony and Doctrine don't fully support entity inheritance.  My reason for thinking so is the incredibly sparse amount of documentation on the subject and remarks on quite a few github issues posts and other blogs how it is "bad practice".

For instance, say I have Mouse, Cat, and Dog which all extend AbstractAnimal, and each has a bunch of common properties such as birthday, weight, etc, and methods such as eats(), sleeps(), etc.  Sorry in advance for using hypothetical entities but I don't think doing so distracts.  I like how inheritance allows me to keep all common properties in a single table, but can let that go.  More importantly, the subset mouse, cat, and dog table shares an ID from the animal table allowing me to associate all animals to some other table (i.e. many-to-one to person whether they are their pet or many-to-many to country whether they are native to a country), and to retrieve a list of animals and filter by some property or type as needed without a bunch of unions.

To me, this sounds like inheritance, but if the products I am using don't support it very well, it doesn't matter.

First question.  Is entity inheritance considered bad practice?  And even if not, is it common for frameworks to limit their level of support for them?

If so, what can I do about it?  Maybe favor composition over inheritance?  Okay, great, I now have a single animal table which makes all my SQL concerns issues go away and I am pretty confident that my serialization issues will also go away. All I need to do is inject each animal with some "thing" to make them a mouse, cat, or dog.

But what do I call this thing?  I've struggled with this topic for a while and asked the same question regarding how to deal with BarCharts, PieCharts, GaugeCharts, LineCharts, etc all being charts but all acting slightly differently, and never really came to any conclusion.

For a non-hypothetical scenario, I have BacnetGateway and ModbusGateway which extend AbstractGateway.  Okay, this one is easy and I change to just having a Gateway and inject either BacnetProtocol or ModbusProtocol.

For another non-hypothetical scenario, I have PhysicalPoint which represents some real environmental parameter, VirtualPoint which represents combining one or more PhysicalPoints or VirtualPoints, and TransformedPoint (feel free to provide a better name) which represents performing some time function such as integrating over a given time.  Currently, they all extend AbstractPoint, but if I was trying to do so with composition, I could inject PointType but don't think doing so makes sense.

For my hypothetical scenario, do I make a DNA interface and inject an Animal with DogDNA to get a dog?

I really need to get my head around this once and for all.  Thanks

I am using PHP and Doctrine to store and manipulate Highchart objects such as the following:

{
    "chart": {
        "type": "bar"
    },
    "xAxis": {
        "categories": ["Africa", "America", "Asia", "Europe", "Oceania"]
        }
    },
    "series": [{
        "name": "Year 1800",
        "data": [107, 31, 635, 203, 2]
    }, {
        "name": "Year 1900",
        "data": [133, 156, 947, 408, 6]
    }, {
        "name": "Year 2000",
        "data": [814, 841, 3714, 727, 31]
    }, {
        "name": "Year 2016",
        "data": [1216, 1001, 4436, 738, 40]
    }]
}

My DB schema is:

BarChart
-id (PK)
-name (string)

BarChartSerie
-id (PK)
-barChartId (FK)
-name (string)
-position (int)

BarChartCategory
-id (PK)
-barChartId (FK)
-name (string)
-position (int)

BarChartNode
-barChartSerie (FK)
-barChartCategory (FK)
-value (decimal)

The chart entity has a collection of serie and category, and  the serie and category entities both contain a reference to the shared node.

I wish to clone the chart entity and thus use __clone() to set the chart, category, and serie entity's' PK to NULL, however, am running into issues as the node entity still has the original entitiy's PKs.

I think maybe I should be creating the entities differently.

Any suggestions how these objects should be created?  Maybe instead have my series contain a collection of nodes and have each of these nodes contain a reference to the applicable category?

Thanks

What are the differences and implications of UTC time and Zulu time?
  

<?php
function getArr(string $time):array
{
    $dateTime = new \DateTime($time);
    return [
        'time'=>$time,
        'timestamp'=> $dateTime->getTimestamp(),
        'dateTime' => $dateTime
    ];
}
$arr = getArr('2020-08-05');  
$arr_z = getArr('2020-08-05T00:00:00Z');  

print_r($arr);
print_r($arr_z);

echo('equal timestamps: '.($arr['timestamp'] === $arr['timestamp']?'true':'false'));

Array
(
    [time] => 2020-08-05
    [timestamp] => 1596585600
    [dateTime] => DateTime Object
        (
            [date] => 2020-08-05 00:00:00.000000
            [timezone_type] => 3
            [timezone] => UTC
        )

)
Array
(
    [time] => 2020-08-05T00:00:00Z
    [timestamp] => 1596585600
    [dateTime] => DateTime Object
        (
            [date] => 2020-08-05 00:00:00.000000
            [timezone_type] => 2
            [timezone] => Z
        )

)
equal timestamps: true