Dhyana is when the mind has no object and no subject. The rest is concentration, which has to be practised.
We should not forget that the mind will be calm as long as you are practising, but it will not destroy itself. The mind will not be destroyed. It will be calm for sometime.
So, to keep the mind calm and destroy it forever is the aim and this is absolutely necessary for freedom.
When there is no mind, this is freedom. When the mind doesn't function, it is freedom.
I don't find any results by concentrating on an object, because it is done with some effort. Some effort is needed between the observer and the object of observation, and this, in between them, this function is effort. When the mind doesn't function and returns to its natural state of calm and peace, this is effortless. This is called "freedom".
To attain this freedom, no effort nor method is necessary. You have not to tread on the beaten track. You have to find your true nature, find out who you are. You have to start there before trying to know anything else.
Leave aside all methods, leave aside everything.
Sit quiet and do not move.
Do not move the mind, do not activate the mind nor the intellect.
Then observe the observer itself and this will be your true nature, from where everything else comes.
This is your own nature.