Thanks for your reply. The hiding of the future seems not to work in my case as I have a change of future promises that need to be done one after another which makes things complicated with hiding the futures. I tested this idea and it seemed to hide the future would not work with future_promises.
The same complications are true for r_bg() function as well. For this purpose, I have to sort of re-write the app from scratch.
How about plumber? Have you ever used plumber APIs in combination with shiny? Do you have any idea how should I apply the idea Graham suggested in the comment above?
Thanks in advance,
Adrian