If Python has been defaulting to dlopen() on AIX systems that support it, there is no reason to maintain the historical, AIX-specific load() support in dynload_aix.c

I believe that dlopen() was introduced on AIX in release 4.3.  The official end of support for AIX 4.3 was 2003, so I doubt there are any customers on extended support, or at least those customers are unlikely to install Python 3.11.