The $request->all(), using “participant[$k][questions][][question_id][$customQuestionId][answer]” and " participant[{{$k}}][name]" shows like:
array:4 [▼
"participant" => array:3 [▼
"general" => array:2 [▼
"name" => "Jake"
"surname" => "K"
]
1 => array:1 [▼
"questions" => array:2 [▼
0 => array:1 [▼
"question_id" => array:1 [▼
1 => array:1 [▼
"answer" => "answer1"
]
]
]
1 => array:1 [▼
"question_id" => array:1 [▼
2 => array:1 [▼
"answer" => "answer2"
]
]
]
]
]
"plus" => array:2 [▼
"name" => "John"
"surname" => "K"
]
]
]