(I realise this is yet another Argon2 "how do I configure" question, but the existing questions I've found don't really help. If I've missed one, happy to have this closed).
Deploying Argon2 (with the Argon2id variant) into a server environment to hash passwords and process site logins - the question we're grappling with is "how much memory to allocate". Now, I'm aware it's "as much as practically possible" but I haven't found any guidance on a lower limit (e.g., something that says something like "below 16MB it's not worth it").
Obviously as iterations can be tuned upwards, we can maintain hardness in that dimension, but at what lower limit of memory would be considered "bad" or at least "not good" for Argon2? If this is purely to help avoid cache hits in a GPU then this would suggest allocations as low as 16MB may be okay, but am I missing something? If it's a case of "16MB okay, 32MB recommended, above 48MB there's nothing gained anything at the current state-of-the-art" that's also fine. I've seen people talk about 1GB allocations - this almost seems overkill?