well, auth depends on the exact case, as an example, some 2FA we deal with it via code and we generate OPT on demand, on some cases, different approaches. One thing worth mentioning is that for auth, we allow you to attach a proxy to an auth session which will allow you to use that same IP with that auth session to reduce issues.
One more thing, we have something called recorder auth session which basicly allows you to use a remote browser to authenticate and then we just save that.