aot_shared_cache, like the other files in that folder, is the prebuilt and prelinked dyld cache for the system frameworks. This is a new feature of Big Sur, whereby these frameworks are only shipped on the OS in this form, rather than as a bunch of .framework or .dylib files. The aot one just happens to be the one for use by Rosetta 2 compiled apps.
None of them will grow in size except via system updates, and only if any system frameworks add significant amounts of code or data.
The actual code cache for user supplied binaries lives in /var/db/oah/, which is a protected location that not even root can browse.