Is it possible to combine different types of plots. For example histograms, scatter plots and or box plots on the same shiny app ?
if possible, how can one go about that without making the code complex ?
You can combine any kind of content on a shiny app but your request about "without making the code complex" is ambiguous, because nobody can know what you would consider complex.
To help us help you, could you please prepare a reproducible example (reprex) illustrating your issue? Please have a look at this guide, to see how to create one for a shiny app