Another sentence I tried - "I wasn't that interested in working on my project today and hence I preferred to stay at home and watch Netflix in spite of the multitude of issues reported." is show as very hard! It makes me question if the original developer of this app has even read good well-known style guides for the English language.

I'd advice you to read a good style manual to understand more about writing and how to use words. One doesn't have to forcibly introduce words that are too complicated. There are good organic ways to write sentences that employ seemingly complex words in a natural way so that readers can understand quite well. The goal should be to elevate the users to get better at reading in addition to conveying your material, IMO.

A good book to read would be Steven Pinker's Sense of Style - https://www.amazon.com/Sense-Style-Thinking-Persons-Writing/....

One doesn't have to degrade their sentences just because we live in the age of attention span deterioration and social media. All of these minor tweaks can help people improve their attention spans by releasing micro dopamine orgasms.