I researched this for hours and I think I got this down.
wifi on ds needs a WEP security system or a OPEN security system. WEP, is totally outdated and your not gonna find it anywhere.
that means the only other viable option is a OPEN wifi system but that's a security risk for your wifi. So what you have to do is this.
Get a ANDROID PHONE, not a iPhone, to my knowledge this is impossible with iphone.
The android also has to have a sim/cellular attached to it, it cant just be blank phone with no service.
you open a hotspot and in the settings of said hotspot change the security settings to open. This is ok because its a hotspot not a fancy wifi router.
from there connect to it from your ds
follow the rest of the instructions of setting up wiimmfi on your ds here
this method works for me, and seems to be the only realistic possible method without buying a whole new router.
wifi on ds needs a WEP security system or a OPEN security system. WEP, is totally outdated and your not gonna find it anywhere.
that means the only other viable option is a OPEN wifi system but that's a security risk for your wifi. So what you have to do is this.
Get a ANDROID PHONE, not a iPhone, to my knowledge this is impossible with iphone.
The android also has to have a sim/cellular attached to it, it cant just be blank phone with no service.
you open a hotspot and in the settings of said hotspot change the security settings to open. This is ok because its a hotspot not a fancy wifi router.
from there connect to it from your ds
follow the rest of the instructions of setting up wiimmfi on your ds here

Connect to Wiimmfi on your DS/3DS Tutorial! | Fandom
I helped @Litbelb with this, so I’m going to help…
animalcrossing.fandom.com
this method works for me, and seems to be the only realistic possible method without buying a whole new router.