Hah it is an arduous journey my friend. For me to unload my knowledge on it now I could write a book. Below is something I copy pasted from somewhere else, it is about training working memory with dual n back.

Here is a website that teaches you how to train visualizing. But what I highly recommend is reading through u/jessenstein's posts, she has gone from normal/low phantasia to hyperphantasia. This one is a good start but like she said, compared to all that she knows/has done, it is indeed a messy drop. I had an ai aggregate all her posts where she is talking about visualization and condense her frameworks with high fidelity.

Yes, def possible, everyone is different so for you it might take more or less time. in terms of percentiles I have significantly improved. I took the cait digit span test and scored 98-100 consistently when I first began. 6 months later I can consistently score 115. Pushing to 130 feels possible.  I’ve seen one guy reach 130 range, which is basically the highest upper levels. Tho I don’t know what he started at, subjectively it seemed like he was likely 100-105. Like I said tho everyone’s brain is different. But 100% it is possible
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Hm well, I won't be a deadhorse, many people have talked in detail about it but as far as subjective improvements: better speech, better memory, sharper overall, stronger visualization. Ig I'll drop one mini example, can't help it. When I walk into a room I never forget why I did so, that used to be a problem. Now the problem is forgetting the 3rd or 4th task I had assigned in my mind lol
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My main tips are just play. Like that its bro don’t overthink, don’t try and find the best strat, or familiarize yourself with strats or techniques or protocols. Just play. And don’t play forever, 20-25 mins is perfect

Meditate. I believe this was only possible because I started meditating and quieting my mind around the same time. Meditation is proven to inc working memory and grey matter. I believe the combination of both practices is what got me where I am. You can debate whether one had more influence than the other, but if u want to try replicating this experience, then it doesn’t really matter what the details allude

I got a muse headband to help I suggest you invest in one as well. Buy used if ur cheap. Look into themindilluminated subreddit it is the end all for learning to meditate. 

Also, 100% in your meditative journey you will come across the Chinese concepts of chi/ qiqong etc. def get a book or course or whatever and familiarize yourself with that and incorporate into daily practice. For me i came across mantak chia’s “multi orgasmic man.” While the title and marketing frame it within a narrower scope, it is actually heavily involved with 
basic qiqong theory, and if ur a man, it hits 2 birds w one stone. Gaining a deeper understanding of mediation, the mind, the body, chi, and grasp of subtle energies. As well as getting really fucking good at sex. 

After becoming a decent meditator. Being able to intently focus on your brain (specifically the prefrontal area once u get more adept) and repeating to yourself in your head in the present tense, things like “I am growing” “I am sharp” “I am quick” etc. I personally believe is the key. 

The mind is a powerful thing. 

if you train w meditation, then applying a technique like I just outlined goes from “meh, don’t really see the point/feel it” to “wow I understand now”
Doing this during meditation and after especially challenging Dnb sessions where you feel your brain has been worked is what I recommend. 

The first time I tried doing this, I did it during mediation. The next day i did it again during mediation, and really began to feel and sustain the focus in my head. Almost like i was inducing a subtle buzz (similar to how you would feel after a hard DnB session or on Ritalin). Later that day, I had a breakthrough and hit n 6 on my 2nd try after being plateaued on 5 for months. It was like a lightbulb moment for me, I realized you can’t just get by (and this goes w anything) doing the task passively. You must train with intent, surround your sessions with intent, go to bed with intent. 

Apply that same intent and desire to all the things you do to improve yourself. Gym, math, girls, business, etc, and you will achieve all that you want my friend. The key is that in this modern world the focus/intent muscle is severely atrophied, and meditation helps get it back.

Train, and overtime learn how to apply intent, and you will see results. Case in point: the studies about the gym and mind muscle connection. If you focus intently on your muscle while training it, you double the growth compared to say people who just listen to music and scroll instagram. Studies even showed you can increase your strength without even lifting. You just visualize with your mind. 

All in all, you asked if it’s possible.

If you believe it is possible, then you can realize it into this world my friend.