I already have a few other articles targeting other key words, and I feel the unique contribution of this one (and the latest version of fbs, which this one aims to spread the word about) is a much better solution for ... Linux GUI programming. But I'll keep in mind what you said. I'm still pretty new to SEO.
When I clicked on the title, I expected to learn about how to create a Linux GUI. This article did not, in any way, shape or form, teach me anything about how to create a Linux GUI. It introduces a tool which solves a problem I'm not sure I'm having, related to packaging (why would I care, it's the distributor's job anyway, no one using Linux should ever have to download an installer manually, ever)
SEO is not about promisig something, making them click, and then giving people something completely different. It's about targeting the needs of a group that has a particular pain, and addressing them well.
I like that the project supports AppImage. I don't suppose fman supports displaying AppImage icons? I've been keeping my eye out for any filemanager that does.
If SEO is the goal, perhaps it's worth looking into keywords along some other directions? A lot of folks who get past the "getting started with Qt" part is going to be interested in the problem of packaging Qt applications (especially where Python is involved, which comes with its own set of difficulties).
If these are the people such an article is relevant for, I doubt "Linux GUI programming" is the kind of stuff they're googling for. After all, they already know a little about that, the problem is how to let their friends use what they wrote already. Meanwhile, people who are googling things like "how to write gui program Linux" probably need help figuring out things like signals and slots, not how to package an application that they can't even write yet.