Samsung phone - What does "OLM" mean for the CSC Code?

I attempted to root my (new) Samsung A24 - and while that worked, I've been having issues with the phone suddenly being unable to make or receive calls after a random number of hours until I reboot it. I'm trying to work through this. While I did flash the phone with firmware that claims to be for my region (NZ - so XNZ), the CSC files don't mention "XNZ" in them, they mention "OLM". I've been unable to find out what this means. I did discover OXM is some kind of universal software, so I'm wondering what OLM stands for, and also wondering if it is appropriate for my region!