I’d also note that COBOL is only one layer of the stack. The real complexity lies in also understanding z/OS (mainframe operating systems), CICS, JCL, and the

I’d also note that COBOL is only one layer of the stack. The real complexity lies in also understanding z/OS (mainframe operating systems), CICS, JCL, and the rest of the mainframe runtime, it’s an entirely parallel computing universe compared to the x86 space.