it would only happen when you are way over the custodial limit, I don't see how this affects onboarding at all
Discussion
Oh you are suggesting that WHEN you get to that limit then you would notify them to send to an onchain wallet? That is fine then. I thought you meant that the user would put link an onchain wallet during onboarding. You could probably recommend some good self custody wallets too at that point. That should get normies away from garbage apps like trust wallet.
the user would get a non-custodial onchain wallet automatically, or they can override it with with their own address.
but they would be forced to have one regardless.
When would their seeds be generated? Because if you make them write down their seeds during onboarding, that might make them drop off.