The fromURI redirection works with both activation and reset password links. I use it to redirect users back to my OIDC app after activation and reset password flows.
${activationLink}?fromURI=https://myoidcapp.com and ${resetPasswordLink}?fromURI=https://myoidcapp.com
You will also have to add the app’s url to trusted origins.
Go to security -> API -> Trusted Origin -> Add Origin enable redirect (and CORS if you need)
Let Okta deal with password and security questions and on success redirect to my app
Hope this helps.
Thanks,