I love Rexx and have used it extensively on IBM mainframes and PC's way back. That said it seems like the ecosystem has moved away from the the types of integrations where Rexx was strong. On IBM mainframes it was always the tight integration with things like CMS and XEDIT that made it great.
If you're using Rexx today on e.g. MacOS or Linux I'd be interested in hearing how that's working for you... My goto for scripting these days would be Python in those environments (or bash).
Oh man, I remember using an XEDIT+Rexx email client back in the day on VM/CMS that was mind blowing for its time. The stuff available for Unix and VMS paled in comparison.
But it definitely was the tight integration with XEDIT and the OS that made Rexx so perfect. I don’t think it would work so well for my modern use cases.
I'd echo what you said, without that ecosystem and integration, perl and python are far better. Personal history: I went from perl in college to REXX because of IBM. However, once I left IBM, I went back to perl and python.
If you're using Rexx today on e.g. MacOS or Linux I'd be interested in hearing how that's working for you... My goto for scripting these days would be Python in those environments (or bash).