currently staring at what's left in a large legacy rails/activerecord app figuring out what to do with. the suffering is real.
That said, for microservice extraction specifically, a bit of creative metaprogramming/monkey patching of AR to identify & categorize your callers is probably easier.
the problem with activerecord is most people usually don't put this in place to begin with because the active record pattern makes it easy not to, which creates a massive pile of spaghetti code long term.