"My understanding has been only intellectual & theoretical.."
Both intellect and the heart are paths. Both are valid. I suspect those with a strong intellect follow that path, and those with strong feeling follow the heart. Neither is better. Neither one is superior.
Nothing will so break the intellect as feeling. And thinking often unseats or stirs up great feeling. In the end, feeling and thought merge, and one feels one's thoughts and thinks one's feelings.
If your thinking mind comes to realize its limit; knows it cannot "get" this, then there can be a relaxation into something outside the constraints of thought.
A great anxiety may need to be experienced when thought is revealed to be inadequate. But, then again, if one considers that thought never did contain Truth, one might be able to move on, knowing that the security thought seemed to provide was never real.
Since thought never was adequate, one realizes that one did survive the illusion! The security was false, but survival was still the fact. In this manner, thinking, though not adequate, provides the proof that one can survive quite well with false security.
This realization may provide some relief in letting go of intellectual understanding, as one sees that it never was adequate, and so your dependency on it was never the security you thought it was.
"I am at a loss where the next step is."
There isn't a next step. You have simply reached the end of finding any security in thinking. Feeling is not going to provide the understanding either.
There is something else. It is called the unknown. It's not something one usually envisions as a place to rest. But in the end, when your mind is spent, and your emotions are spent, the unknown may be the only place you can find to rest. If you embrace the unknown, at least it is sure. It will remain unknown.
One realizes that one acted and reacted in unknowing, even when one thought one knew. It's like loosing your security blanket. It never really protected you from anything. You just thought it did.
After the unknown, a few lucky souls experience something else, a subjective knowing beyond thinking or feeling. It is a knowing that is unshakable. In the Christian tradition it has been described as "The peace that passeth understanding."
This knowing is not assailable by thought, because it is beyond it. It is not assailable by feeling either. The mystics called these experiences "unitive." Oneness with God is another description. The East calls these satori.
Keep in mind that the ecstasies of the the subjective experience, or satori, also do not last. But the taste provides a foundation in unknowing knowing. One is then neither happy nor sad, but just O.K. Just O.K. is a good thing. No more searching after high or low. Just this.
Soon enough one finds that one can rest, even function in unknowing. Thoughts may come and go, but they are not held on to. Feeling states come and go, but they are not held on to.
Charlie Hayes says “The difference between an intellectual understanding and AWARENESS noticing itself is incredible “
I would ask Charlie. He may be able to provide clarification. He is speaking from beyond the little mind trying to grasp. It's called non dual understanding. Simple, but apparently not simple to come by.
"I am groping in the dark."
That's not a bad thing. It is your mind that feels in the dark. Your feelings may also be groping in the dark. So what is beyond these two? The unknown. Let the unknown become your friend. Peace can be found there.
Lastly, consider these words of the great Sufi poet, Rumi.
"Out beyond ideas of Wrongdoing and Right doing, there is a field. I'll meet you there. When the soul lies down in that grass, the world is too full to talk about. Ideas, language, and even the phrase 'each other' doesn't make any sense."
-Rumi, c. 532 A.D.
There is no "next step."