You can implement Sign out functionality wherein it will sign the user out of their current Okta session, revoke the issued access and refresh tokens and will clear all tokens stored locally.
The signout() method takes in different options as mentioned here - GitHub - okta/okta-auth-js: The official js wrapper around Okta's auth API
Setting clearTokensBeforeRedirect to true will ensure that all the local tokens are removed before the logout redirect is initiated