I think you need to adjust your system locale setting in R for the behaviour you wish.
I could switch back and forth (in R4.2.1) with your example
between Sys.setlocale(locale = "en_US.UTF-8")
and Sys.setlocale(locale = "en_US")
and see a view that didnt work and a view that did.
p.s. i use usethis package to conveniently edit my r profile, to set such settings so I get continuity between my sessions