You can set it (in the Profile Options) to load the forum profile page when a user first visits the forum. So that might do what you need. But remember that users do not register for the 'forum'. They register for the 'website' of which the forum is just a part.
Mr Yellow ,thanks for the point out, never thought would take you so much time on this topic, thank you.
So I then set the login and registration like this: screenshot
And tried to register a new member on my side, it works like this:
1.set username and email address, registration email sent
2.go to email box, click the link the the registration email to set password
3.login with the new password
and sadly in my case, it still redirects to woocommerce my account page, lol
I don't know whether woocommerce has a higher authority, so sp's redirect didn't work