Modeling humans requires human anatomy study. It's extremely unlikely that you will ever model a believably proportioned human unless you have fully learned the skeletal and muscular structure of the human body. Once you have made yourself an expert on human anatomy, modeling a human body will feel no different from modeling a chair or a coffee cup.
I know that may sound like a lot of work that you won't feel like doing! But trust me on this one, if you try to start modeling humans (or anything else) without doing the proper anatomy study first, you will always feel lost and confused like you have no idea what you are doing and everything you make looks wrong and you won't know why.
Youtube channels "Sam Webster" and "Viren Kariya" have a lot of excellent anatomy videos. Kariya has real human bones that he holds in his hands and moves around and explains every tiny detail, and Webster has muscular models, as well as videos about organs, blood vessels, all sorts of anatomy-related material. But, these things will only get you started. You'll also want to take advantage of the information in encyclopedias, wikipedia, other youtube channels, etc.
Once you know the anatomy of the thing you want to model, you'll feel like, 'wow, I can't believe this was ever a challenge for me.' This is the solution to the roadblock you are experiencing, don't try to skip it. It is the answer, even if it is not the answer you want.
Note that the current standard of photorealism is scanned models. No manner of modeling technique will reproduce the same graphic impression of a scanned model. If you're modeling humans yourself, don't let yourself get wound up in the trap of comparing your best work to scanned models. That will only ever make you feel inadequate when your work may be perfectly fine.