How can we unify the URLs without using 302/301 redirects, as they are not SEO-friendly?

Not all links will go through 302/301 redirects, because there are many forms of links in the configuration, redirection will only occur when one of the parameters is wrong.

<h5 class="text-wrap text-break">
              {{if $.useTitle }}
              <a class="link-dark" href="{{$.baseURL}}/questions/{{.ID}}/{{urlTitle .Title}}"
                >{{.Title}}</a
              >
              {{else}}
              <a class="link-dark" href="{{$.baseURL}}/questions/{{.ID}}">{{.Title}}</a>
              {{end}}
            </h5>

There is indeed a problem with the logic in the template you mentioned above, and we will fix it in version 1.4.1.

You can follow this ISSU to get the repair progress.