foxy-map.ts

type User = { name: string };
type MyModel = {
    name: string;
    users: User[];
}

type OnlyArrays<TModel> = Exclude<{ [key in keyof TModel]?: TModel[key] extends any[] ? key : never }[keyof TModel], undefined>;

type Numbers = '0' | '1' | '2' | '3' | '4' | '5';
type StringKeyof<TModel> = keyof TModel extends string ? keyof TModel : never;
type Keys<TModel extends { [key: string]: any }, TProp extends string> = `${TProp}.${Numbers}.${StringKeyof<TModel>}`;

type Mapped<TValue> = Partial<{ [key in Keys<User, OnlyArrays<MyModel>>]: TValue }>;

const test: Mapped<string> = {
    "users.0.name": 'test',
}