Yes, RStudio is (as of the most recent version, 1.4.1717) compatible with the M1 processor. It isn't fully M1 optimized, but it is able to use R built for M1, so your R code will get the benefit of the M1's speed.
Most of the problems have come from people either (a) using a version of RStudio too old to support the M1, or (b) accidentally downloading the wrong version of R (there are different builds for Apple Silicon and the older Intel chips).