Problem using json_array_elements to extract values from array of JSON Objects in Postgres

I have the following code in which I am trying to extract JSON as follows:

DROP TABLE IF EXISTS tmp2;
 CREATE TEMP  table tmp2 (
      c TEXT
    );

insert into tmp2 values
(        
N'{"SerialNumber":"907578","SoftwareVersion":"1.2.777","Build":"4829","ProductCode":"TR-3500-A","BuildDate":null,"Description":"Study desk","ConnectionType":2,"Capabilities":[2,3],
        "ChannelListDto":[
            {"ChannelId":0,"ConversionType":0,"DeviceSerialNumber":null,"Dimension":"","FixedName":null,"Name":"test2","InstrumentationChannel":-1,"IsAlarmable":false,"IsInternal":true,"IsEnableable":false,"IsEnabled":false,"JournalledReadingBytes":0,"LowerLimit":null,"Precision":null,"Symbol":"","TypeId":5,"UpperLimit":null},
            {"ChannelId":1,"ConversionType":0,"DeviceSerialNumber":null,"Dimension":"","FixedName":null,"Name":null,"InstrumentationChannel":-1,"IsAlarmable":false,"IsInternal":true,"IsEnableable":false,"IsEnabled":false,"JournalledReadingBytes":0,"LowerLimit":null,"Precision":null,"Symbol":"","TypeId":5,"UpperLimit":null},
            {"ChannelId":2,"ConversionType":0,"DeviceSerialNumber":null,"Dimension":"","FixedName":null,"Name":null,"InstrumentationChannel":-1,"IsAlarmable":false,"IsInternal":true,"IsEnableable":false,"IsEnabled":false,"JournalledReadingBytes":0,"LowerLimit":null,"Precision":null,"Symbol":"","TypeId":5,"UpperLimit":null}
         ]
        }'
)

Now i want to use some code to extract the information from each of the elements in the ChannelListDTo as follows:

select c::json ->> 'SerialNumber' as SerialNumber,
       cto ->> 'ChannelId'::INT   AS channelid,
       cto ->> 'ChannelName'      AS ChannelName
from tmp2
CROSS JOIN LATERAL json_array_elements(c::json ->'ChannelListDto') Channels(cto);

However I am getting the following error:

[2024-01-11 17:54:14] [22P02] ERROR: invalid input syntax for type integer: "ChannelId"
[2024-01-11 17:54:14] Position: 122

I want to get the following results:

DeviceSerialNumber channelID   ChannelName                             IsInternal        
------------------ ----------- --------------------------------------- ----------- 
907578             0           test2                                   1          
907578             1                                                   1           
907578             2                                                   1       

I have tried the following :

select c::json ->> 'SerialNumber' as SerialNumber,
       Channels.cto --> 'ChannelID',
from tmp2
CROSS JOIN LATERAl json_array_elements(c::json ->'ChannelListDto') Channels(cto);

And this yields the following:

So how can I extract the individual elements (ChannelID, ConversionType, IsInternal etc) out of the ChannelListDTO array of JSON Objects

SELECT c::json ->> 'SerialNumber' AS "SerialNumber",
       (cto ->> 'ChannelId')::INT AS "ChannelId",
       cto ->> 'Name'             AS "ChannelName"
FROM tmp2, json_array_elements(c::json ->'ChannelListDto') AS "Channels"(cto);

1. As already pointed out, you need parentheses to make sure it's the output of cto->>'ChannelId' that gets cast to ::int. Otherwise the cast takes precendence, so you end up first attempting this 'ChannelId'::int before it's given to ->>, which gives you the error since that text won't work as a number.
2. You can pretty safely trade CROSS JOIN LATERAL for just a comma , - the fact that the set-returning function relies on a field taken from tmp2 implies the rest.
3. You need to double-quote all your mixed-case identifiers, otherwise they will all get folded to lowercase.
4. It seems that you actually wanted cto->>'Name', because the json you showed doesn't have a 'ChannelName' key in it.
5. The --> in Channels.cto --> 'ChannelID', isn't an operator. You just selected the entire Channels.cto and then -- started an end-of-line comment.

Demo at db<>fiddle