I'm not a medical authority, so all I can do is reply based on my extensive reading on this topic. I am also a (younger) AF patient, currently in NSR because of a successful ablation.
Ablating an AV node will do nothing for controlling AF. The problem with AF is a 'direct' line of signaling from rogue cells that have grown in the substrate in one or more of the six walls of the left atrium. These rogue cells don't use the AV node. All the AV node does is to pass on the SA node's original signal and send it down via the Bundle of His and thence the Purkinje fibers along the bundle branches that feed signals to the two ventricles. There is one possibility, though, and it's somewhat rare: the AV node may issue a 're-entrant' signal that travels up to the left atrium and from there is causes the atrium to beat. This beat won't be timed with the original SA signal just milliseconds before it, so the atrium will beat twice. And the timing will be wrong and counterproductive for the heart's intended function as a sequentially firing set of four separate pumps. That your previous several ablations have failed suggests to me that your electrophysiologist thinks that this might be what's happening, and he wants to neutralize the AV node. If that must be, then yes, you will be solely reliant on a pacemaker. Your SA node would still work, and it would control your atria if allowed to by the pacemaker. And this is where true experts have to adjust the pacemaker so that it 'paces' the SA node accurately and timed just milliseconds later to signal the ventricles to beat...AFTER they have been pumped full of blood by the two atria above them. During AF, the quivering means the left ventricle often never gets filled, and its pumped volume of oxygenate blood to the rest of the body falls, sometimes dangerously low.
It all depends on your heart's state, how advanced it is in terms of degradation due to long periods of uncontrolled AF. If your heart is in reasonably good condition, and your EP doesn't want you sliding further due to AF, then an AV node ablation will at least control the rapid ventricular rate if you have what is called 'rapid ventricular response' to the AF that is happening. This was my problem, and it's very common: the heart beats irregularly during AF, but the ventricles are 'sympathetic' and want to beat in concert. This is not good, not for long. An AV node nuke may control that IF it's a problem for you, but it may also stop that re-entrant circuit and you'll possibly revert to NSR quickly...in seconds.
Remember, none of this is from an expert. If I have given you some concepts to consider, maybe they can help you to formulate some questions to your cardiologist or EP. From there, you should be in charge, and hopefully better off.
Take care.