Invitation Redemption does still work, but as of January 4, 2021 Google deprecated its WebView sign-in support to avoid the risk of MITMN attacks. If you’re using Google federation or self-service sign-up with Gmail, you should test your line-of-business native applications for compatibility.
Additionally, as of October 2021, Microsoft will no longer support the redemption of invitations by creating unmanaged Azure AD accounts and tenants for B2B collaboration scenarios. They recommend customers prepare to opt into email one-time passcode authentication.