https://screenrant.com/star-trek-enterprise-william-shatner-save-too-late/

Star Trek: Enterprise hoped to have William Shatner appear in season 4, but the writing was on the wall for Scott Bakula's Star Trek prequel.

William Shatner almost guest starred on Star Trek: Enterprise (https://www.handitv.com/allstartrek/stories/william-shatner-almost-guest-starred-on-star-trek-enterprise)

We were so close to seeing Shatner return to the final frontier!