As others have said.
You will need to enable 2FA on your Twitch Account. There are several ways to do this, Twitch is using a third party service to do this called authy whom primarily send your Txt Messages with your 2fa code. (most other places tend to do this as the backup rather than the primary but it’s a toss up)
Once you have done this you can invite your Guild Leaders to use the same account via
But all users should have 2FA enabled on your account for your security.
https://help.twitch.tv/s/article/two-factor-authentication-with-authy
Covers 2FA for Twitch.
I will not be surprised, if Twitch requires 2FA for ALL streamers at some point, but even if you have a older account will will require 2FA for Affiliate and above in order to protect your details.
You already gave your Email address and no it’s not illegal, it’s standard security practices to help protect, you, your account and the platform