I also am afflicted with this curse. I can make worlds and characters hand over fist. It took me an embarrassingly long time to realize I just didn't actually have that many stories between them all, and even when I was able to outline "season arc" plot points, doing the actual episode-by-episode, chapter-by-chapter writing to get there was just one wall of writer's block after the other. I kept making up "series ideas" by throwing together or making new characters to have adventures in a creative world, but I never really had any desire to just do "the generic adventures of this superhero team", despite chasing that for so long.
A lot of my characters, even the ones I go out of my way to have more colorful personalities, tend to feel reserved, competent, level-headed, and/or world-weary by default. Even my hot-blooded emotional types tend to be more introspective than they probably should be, though I do also like that about them. And while I personally find that refreshing to a point, it does end up meaning that such casts may not be particularly compelling.
I also have other hang-ups that get in the way, but I won't whinge about them all here.
Frankly, as I've found, there is no system. There are never any universal band-aids to writing problems, everyone's process is different. People can suggest things to you day and night, but if it's antithetical to how your creativity naturally flows, then it's going to be hard for any of it to set in. Character is key to getting people to care about your narrative, first and foremost, but if your brain it stubbornly wired for world-building and not character building, its going to be a much bigger struggle than those writers who naturally start with a character struggle.
That said, isn't impossible, and I don't mean to be discouraging. For me, when writing Graven, it came down to really forcing myself to dig past all the world-building fluff and neat character ideas, and finding some kind of theme and character motive that I could resonate with. It was difficult to do, because it's not how my creativity naturally goes, and I spent about three straight weeks sulking and brooding until it finally came to me. And even since then, I've struggled to repeat that success with another story as of yet.
Even though its advice I struggle with, thinking about theme and a conflict that really emotionally resonates you, can help you focus your story. Not that every single chapter has to be in lock-step with said theme, web serials are allowed to sprawl out some, but a theme can help add that coherency you're looking for.
Graven's main theme was about "fuck-ups trying to make things right". Every major character, the main conflict of the story itself, was in some way reflective of that thinking. When designing the characters, I kept that theme in mind, and it helped shape their motivations, which guided me on what direction to take the characters. When designing the world, it helped me narrow down the important elements I wanted to include to convey the tone of the story, made me think about what kind of circumstances would have occurred to put these characters in their situation. When outlining the story, it helped me figure out what story beats were really important, and actually decide which of the potential story paths to cut out in the interest of not meandering aimlessly.
Now, maybe for you, it isn't theme, exactly, but maybe there is a character you might resonate with, and their personal development is what hooks you. And thus, figuring out how the world and the plot facilitate that development can help you make the decisions to streamline the story into the meatiest, most compelling version. Although it is an old, failed project, I've had at least one story that was shaped largely by the main characters.
I guess my advice here is "figure out the focus" of your story. Good luck.