Better way to convert the object field to nested type field

[Prabaharan_Kathiresa (Prabaharan Kathiresan)]

Hi Team

We have an index with object field, we are planning to improve the object field into nested type (array of objects).

ie.

{
"name": "Adam",
"car" : {
"name": "Maruthi",
"modelyear": "2005"
}
}

we are trying to store the documents from the above one to below one

{
"name": "ABC",
"car" : [
{
"name": "Maruthi",
"modelyear": "2005"
},
{
"name": "HONDA",
"modelyear": "2008"
}
}

My Question is

1. if I do the search query with car.name="Maruthi" will return both documents? or one with nested type will return.

2. what should be the better way to update the existing index mapping? I see articles saying elastic will not support updating the existing index mapping.

My elastic server version is 6.8.5.

Team, any suggestions or any feedback on the question.