bash associative arrays are fantastic, I've made heavy use of them, but be warned that there have been several memory leaks in the implementation. (Sorry, no version notes, once we realized this, we rewrote a key component in C.)
IIRC, the latest bash addresses all of these, but that doesn't help too much if you are stuck with an older, stable OS, e.g., RHEL 7 or 8; even 9 likely has a few remaining.
These leaks become an issue if you have a long running bash script with frequent adds and updates. The update leak can be mitigated somewhat by calling unset, e.g., unset a[b], before updating, but only partially (again, apologies, no notes, just the memory of the discovery and the need to drop bash).
I'd agree with the idea that bash wasn't the best choice for this purpose in the first place, but there was history and other technical debt involved.