It's been less than 3 days, and thanks to pmur002, @malcolmbarrett @ellakaye and everyone else at #RSprint2023 a patch has been made and accepted into R!!
R now supports 3 and 4 digit hex codes!
https://github.com/wch/r-source/commit/0cad8c3fa75f402db464cbfde93284106a12a69f

