is one to one relationship bad strategy

Question

User always has one Wallet. One Wallet belongs always to one User.

Since I want to separate money wallet related properties I was create Wallet object and to be able

Answer 1

No it's fine. It's not just about relationships but object orientation. Fundamentaly a Wallet is not an unseverable part of a Person.

Looking beyond that, whilst the wallet might belong to a specific 'John' now, 'James' might be given it as a present. From the data perspective it's much better to just change the WalletId fields of John and James of which one may be null (although not in your case) if they don't have a wallet.