The R console can only support primitive coloring, and not offer you control over font and fine presentation details by virtue of what it is; similarly R studio table viewer is primitive and not intended to be used as a presentational tool. Therefore there is a sort of divide you should conceptualise between working data structures for calculation, and finished presentational products such as attractive HTML tables fit for reporting.
If you would like to transform a data.frame for the purpose of presentation you should look into using an appropriate package that can render a table visually for presentation/reporting.
Perhaps gt is a good choice.
Easily Create Presentation-Ready Display Tables • gt (rstudio.com)