Nitpicking… OSI model, not ISO… and TCP/IP was the counterpart to the rather rigid OSI model, so even when people like to talk in terms of OSI layers, they strictly speaking don’t apply so rigidly to the layers in TCP/IP, which in reality are far looser defined.
As for the other stack relevant to the topic, the 802.11 wifi stack - that one is ISO
In general I would suggest not doing wifi with the Amiga itself, and rather connect the Amiga using ethernet to something more capable, with active support, that also does modern wifi (not just 802.11b) and modern encryption. As a bonus, the Amiga will not waste lots of precious CPU on just being online.