Interesting, why do you advise people to stay away from Shiny?
It tries to do functional programming, but the documentation is not satisfying. The responses and behaviour is perplexing.
I spent around 5—10 hours trying to get a Shiny GUI to work and eventually got to the conclusion that 1) if you want a big project do all the frontend stuff in something else, like JS and 2) if you want a small project try something established (I am not advocating, it's just an example) like Power BI.