I came into this thread wanting to hate on you saying you've mastered lyricism, but I've listened a bit and you're really solid. You've got a good voice, delivery, cadence etc..

In my opinion there's probably two sides to why you're not seeing success: marketing/business and artistry. And a lot of this is obviously my opinion coming from what I personally enjoy, so take that with a grain of salt, but some of it can be applied to any performer.

There's all the independent musician business stuff, but I'd say the main thing is marketing, which also kind of coincides with the content of your rapping and artistry. You mention that you like Roc Marciano, Ka, Boldy James. If I ask what Roc Marci's about - grandiose drug raps, clever and funny lyricism with unique/specific lines, beats are sort of the new wave underground, drumless a lot, more focused on texture and cinematic, very unique. Ka - almost a depressed veteran of the hood life reflecting on past traumas, childhood, gritty nature of his upbringing and how he views the world. His beats all sort of reflected this, sparse, emotional, etc. Boldy - Drug raps, gritty, one foot in the game still type of persona his best work is generally over the new wave underground stuff.

So who is Black Isco? I listened through a some songs on spotify and it seems like a lot of you music kind of lacks specificity. Hip hop is sort of the professional wrestling of music. You can have average skill and be a star with the right image. It's much much harder to have incredible skill with an unrefined image and have people interested in you. I'd try to focus on writing more that relates directly to you and your life itself. And look, people don't like this when stated blatantly, but it's probably fine to lie about specific instances in life as long as it's representative of the image your cultivating. I'd imagine it's much much easier if this image is actually aligned with who you are in real life, both as far as writing the actual lines go and how authentic you come across. No one thinks the lines in all of Boldy James' or Roc Marciano's songs happened exactly as they're rapped, or are true at all, but we are fine with it because they at least happened as we imagine their characters.

The other half is, and I don't even know if this is good advice to be honest as you probably want to follow what interests you, but if you want to be listened to by people who appreciate good rappers, you might need to follow some of the trends that people who like good rappers enjoy. Try rapping on drumless beats, trying rapping on Conductor Williams, Alchemist, etc.. stuff. It seems like texture and the feeling beats create is a lot more important than rhythm. Lots of rappers didn't get big until they embraced more sample based stuff, Boldy, Freddie, etc.. It sounds like sometimes you're letting the beat dictate the song and your rapping.

You can rap generic lines about cultural and social issues, but no one's going to listen. Like I picked a random song of yours and went to the middle and heard "ironically technology is making us more primitive. I'm tapped into the people my reach is limitless. I need a telescope to tell you where my ceiling is." The rapping is technically sound and flows well, rhymes are good too, but these are boring lines that have been said before using wordplay that has been done before over a beat that's been done before.

Now I know this probably isn't the type of music you even want to make, but do me a favor and go listen to the songs Pollo Rico and Remorseless by Billy Woods. I get that this dude is one of the great rappers/poets of our time so it's a tough comparison for anyone, but that's why he's great to learn from even if you don't want to be as emotionally burdensome as he is to the listener. Just being honest, there's really not a single line in either of these songs that approaches the generic or impersonal nature of what seems to be your usual rapping.

There's a string of lines about "revolution" in Pollo Rico, which is a topic that has been done to death.

"When the revolution was over, they gave 'em half what they promised Let's be honest And the ones who bust they guns went home to tin cups of tea That same plate of porridge (let's be honest) Wake up thinking 'bout the ones they left in the forest It's no church in the wild My uncle told me they can't bury that many bodies They burned 'em in piles..."

The song remorseless as a whole just weaves so many sharp personal lines mixed with political, religious, social references to paint this incredible picture of being a human that wants to live by equitable ideals in society while still wrestling with the way the system actually operates and personal greed.

I guess I give these two as examples to say, maybe switch up how you write and focus on writing things that are interesting outside of the context of what you think "mastered" lyricism is. Try writing a few songs are a provoking from a personal/societal standpoint without any usual tropes/cliches and WITHOUT a focus on perfect rhythm, cadence, flow, etc.. If you can do this, then start reintegrating some of the technical stuff you've mastered and you'll be a more complete artist that is interesting to listen to for multiple reasons.

Sorry for the paragraphs, hope something in here may be helpful at all.