Merging two objects based on key value - php

Question

I have two objects from an API I am trying to merge, one is a list of available subscription packages and one is a list of the current user's active subscription's and the corresponding status.
The first object looks like this:
This\Collection Object
(
[object] => list
[data] => Array
(
[0] => This\Product Object
(
[id] => 444
[name] => Test Plan 4
)
[1] => This\Product Object
(
[id] => 333
[name] => Test Plan 3
)
[2] => This\Product Object
(
[id] => 222
[name] => Test Plan 2
)
[3] => This\Product Object
(
[id] => 111
[name] => Test Plan 1
)
)
[has_more] =>
)
This second object looks like this:
Array
(
[0] => This\Subscription Object
(
[id] => sub_xxx
[current_period_end] => 1670307654
[current_period_start] => 1667715654
[plan] => This\Plan Object
(
[currency] => usd
[product] => 111
)
[start_date] => 1667715654
[status] => active
)
[1] => This\Subscription Object
(
[id] => sub_xxx
[current_period_end] => 1770507654
[current_period_start] => 1767715454
[plan] => This\Plan Object
(
[currency] => usd
[product] => 333
)
[start_date] => 1767715654
[status] => active
)
)
I want to combine the second object with the first object if subscription->plan->product matches product->id so it would look something like this:
This\Collection Object
(
[object] => list
[data] => Array
(
[0] => This\Product Object
(
[id] => 444
[name] => Test Plan 4
)
[1] => This\Product Object
(
[id] => 333
[name] => Test Plan 3
[subscription] => This\Subscription Object
(
[id] => sub_xxx
[current_period_end] => 1770507654
[current_period_start] => 1767715454
[plan] => This\Plan Object
(
[currency] => usd
[product] => 333
)
[start_date] => 1767715654
[status] => active
)
)
[2] => This\Product Object
(
[id] => 222
[name] => Test Plan 2
)
[3] => This\Product Object
(
[id] => 111
[name] => Test Plan 1
[subscription] => This\Subscription Object
(
[id] => sub_xxx
[current_period_end] => 1670307654
[current_period_start] => 1667715654
[plan] => This\Plan Object
(
[currency] => usd
[product] => 111
)
[start_date] => 1667715654
[status] => active
)
)
)
[has_more] =>
)
I know I can perform two foreach loops on each object and turn them into arrays with the revenant data I need and combine them that way, but I would rather merge them complete as objects.
How can I merge/combine these two in PHP?
Edit: This was my attempt at merging the two, but I am lost on how to actually make it work:
foreach($array1 as $product) {
foreach($array2 as $subscription) {
if ($subscription->plan->product == $product->id){
//how do I append to the object in the right place (where the 0 is)?
$array1->data[0]->subscription = $subscription->plan;
}
}
}