After posting my reply yesterday, I did track down a ARM64 version of RStudio and began the following edited version of the earlier post. But because I am relatively new to this forum, my ability to post it was postponed while an administrator inspected the earlier post. I tried to write the following to help others who find themselves in the same situation.
Thanks. This is extremely helpful!
From the RStudio IDE Release History I learned that Version 1.4.1717 ("Juliet Rose") released on 2021-06-01 includes:
Support for the upcoming R 4.1.0 release, including the new
\(x) function shorthand, and new graphics engineRStudio Desktop for macOS adds support for the Apple Silicon (aarch64) builds of R
It wasn't clear to me if this entire version, rather than just the graphics engine it uses, supports Apple Silicon.
But based on this information I was able to track down "Older Versions of RStudio" and from there the installer for "Juliet Rose." Then I downloaded and installed the macOS version, which actually turned out to be 'version 4.1.2 (2021-11-01) -- "Bird Hippie"' and runs natively on my ARM64 MacBook Pro without Rosetta!
Notice that "Ghost Orchid" was released on 2021-09-27 and ostensibly began calendar versioning. But "Bird Hippie" was released over a month later and still uses the semantic versioning conventions.
Suggestion for RStudio PBC: tracing down all the different names and version numbers used during this transition period may be a time-consuming task with relatively little gain; instead, add a page with a table showing the correspondences between Release Date, Release Name, semantic version number, and calendar version number. Notice that semantic numbers are also inconsistent (e.g., 1.4.1717 followed by 4.1.2), so the table may require a fifth column.