Other answers have already given great tips about asking your supervisor about publishing and its potential benefits for your career. I'll just address some things you'd need to consider if you do decide to publish, also to give you a realistic view of what you'd have to do to address the "awkward length".
Theses are for students to show what they know and often they include some quite detailed definitions and descriptions of concepts and methods. However, the target audience of a specialized journal does not necessarily need a detailed description of the history of theory X. Thus, shorten or omit any literature reviews that might sound new to an undergraduate student but would seem "obvious" to the target audience.
Omit any descriptions not directly relevant to your topic: if you focus on theory X, there is no need for an extended description of related theories Y and Z. If you really need to address theory Y, keep it concise or refer readers to sources where it has been discussed in greater detail (e.g. "For an overview of theory Y, see Smith (2010)...").
When it comes to reporting your own arguments, focus on the important stuff, the "beef". If you have, say, 1 main argument and 2 less important arguments, consider focusing on the most important one. Do not squeeze in too many ideas into a 8-10k words article as you won't have enough space to discuss them in detail, leading to a superficial analysis. Having many arguments may also make the article feel unfocused, which could likewise easily lead to rejection by peer-reviewers. Turning your well constructed thesis into an equally well constructed article is not a matter of copy-paste: it would mean a lot of rewriting and restructuring, so consider whether it is worth the effort. Note that an academic might be inclined to split 3 arguments into 2-3 articles to give each idea the space it deserves!
If you decide to publish, check the journal's submission guidelines for the word count or structure you should aim for. Consider analyzing the structure of a couple of top articles in the journal(s) you want to publish in. Rather than focusing on the content/research, look at the sections and subsections included (whether or not they actually have subheadings): what sections do you find? How do they build on each other? How long are they relative to each other and to the paper as a whole, (e.g. Introduction = 1/20 pages, Core concepts and literature review = 2/20 pages, Argument A = 7/20, Argument B = 6/20...)? This exercise helps you get an idea of what to include and how much space to account for each section.
Finally, you need to have your text revised and proofread before submitting to journal - by your supervisor (if they are willing), by the university proofreading services, or by a proofreader/reviser specializing in academic texts. Many manuscripts get rejected because even if the vocabulary and grammar is correct and professional, the style sounds "immature" in the ears of more experienced academics, who generally have a lot of experience reading student writing. By the time you are doing a PhD and look back at your undergraduate thesis, you'll probably feel the same way (source: personal experience). The problem is, an immature style can make the reviewer feel the text and arguments are trivial and unworthy of publishing. Having a second or third pair of eyes to look at your text before submission can also help you identify unnecessary repetition or unclear ideas.
