I don’t think we will ever see an updated 8 Plus for one reason: it might be the most popular iPhone released and would hurt sales figures of the rest of the phones.I would love the SE4 to have the body of the 8 plus with Touch ID but I am sure I am in a severe minority on this.
What Apple needs to do is upgrade the 8 Plus and make it the same price as the Pro Max. People would gladly buy it at $1,200 USD.