Usar

• función plana => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat

• función de filtro => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find

Devolverá el primer valor que satisfaga la condición.

Algo como:

 const data = [ [{_id: 1}, {_id: 2}, {_id: 2}, {_id: '60da3d5ce6cdd45d6dbc56bd'}], [{_id: 1}, {_id: 2}, {_id: 2}], [{_id: 1}, {_id: 2}, {_id: 2}] ] data.flat().find(e => e._id === '60da3d5ce6cdd45d6dbc56bd') // output { _id: '60da3d5ce6cdd45d6dbc56bd' }

funciona bien