Using jargon like "upskill" is indicative of the kind of thinking that leads to bad writing. It's a very easy to habit to fall into where you "write" by just sort of stitching together the nearest cliches, phrases, and jargon that come to mind. It's how we often talk and how we often write.
Unfortunately, writing like that is never good. By being a lazy pastiche of the familiar, it swaddles what you're actually trying to say in layers of non-information carrying fluff.
To improve your writing, you have to break that habit. You have to train yourself to introduce deliberate thought into the step between "vague idea in my head" and "linear sequence of words".
When you force yourself to cut out the jargon, that inconvient friction gives you a moment's pause to remind yourself to think about what you're trying to say.
Also, jargon usally has negative value. It says the same thing as simpler non-jargon words, but mixes some in-group signalling with it. In-group signalling can be a useful positive signal ("Trust me, I know what I'm talking about because you can see that I've absorbed the culture") but it can also be alienating for readers that don't feel like comfortable members of the tribe.
I try to use a little jargon here and there just to reassure people that I know the lingo and context of the local culture but otherwise I mostly focus on saying what I mean.