Actually, I contacted the government agency overseeing this and told them I did not have a smartphone for health reasons. They said I would have to undertake some kind of procedures ahead of time, but I could still enter Japan without a smartphone. However, I was concerned about quarantining upon return, if they deemed it necessary. When I asked whether they would have quarantine facilities without Wi-Fi, they just gave me the brush off. Since I have two other strikes against me (unjabbinated like you, and pro-Russia), I'd better sit still for a while until we can get some recognition as disabled.
Meanwhile, Japan's leading activist for EHS and MCS human rights has been forced to flee her home in Sapporo. The strategy she has promoted is "shelter in place," since Japan lacks places to flee. Her house was well shielded, but the noise from construction of a campground next to her house was too much on top of the increasing electromagnetic burden we are all dealing with.