Start by banning words like "upskill" and "learnings"
"Communication" starts with realizing that you have to meet people where they are, not expect them to adopt your style. You have to have some respect for them.
"Avoid unnecessary adverbs" would be another easy one ("unhelpfully signalling your disdain")
Castigating people for word choices that you personally dislike while simultaneously advising them to "not expect them to adopt your style" is hilarious.
Corporate is widely and justifiably condemned. It's not just a personal thing. Even on this thread.
Calling it "hilarious" was definitely the work of a flamer though.
Surely if the OP is trying to help their team to communicate in a corporate environment, then teaching them the shibboleths like "upskill" will be helpful to (as you rightly suggest) meet the readers where they are? The team will be free to use them or not, as they choose. Whereas "banning" those words can only handicap their ability to corporate-cosplay, if that's something they want to do.
If you have respect for your readers, then you use language they can relate to.
Regardless: I suggest you check the sibling thread (https://news.ycombinator.com/item?id=33805016), where we explore more relevant considerations - not just "what group are you masquerading as?", but also "does the use of this jargon result in fuzzy thinking or poor structure independent of the actual words used?" (/u/munificent suggests yes, I suggest that they're often correlated but there's not necessarily a causal link - cutting out those phrases will not _in itself_ result in better-considered, clearer, more-meaningful communication)
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.