Unfortunately, this is not possible. The only remedy is to reset the keyboard dictionary (Settings -> General -> Reset -> Reset keyboard dictionary) and it is also quite limited. It’s an all or nothing scenario, which means that if you accidentally add a misspelled word, you can not just remove it, all your custom words must go.
This is definitely something you want to send feedback to: https://apple.com/feedback/iphone
However, there is a potential solution, if you are willing to use a third-party keyboard – Microsoft Swiftkeys. I have been considering it for a while now and have found it quite capable. Specifically for your question, it has the ability to delete individual automatically predicted words instead of having to remove the entire dictionary. It is conditional on logging in to the keyboard shortcut account so that it can back up and save your dictionary and settings.
Swiftkeys is free with in-app purchases that just seem to be the themes. So if you stick to just the included themes, you will not be out of pocket for this app.
Keep in mind that this is a third-party keyboard and will require “Full Access” for full functionality. This means some third-party keyboards can see and send what you type back to the developers. Google’s keyboard, although strong in features, seems to be a nightmare about privacy. Although I do not trust Microsoft completely, I trust them much more than I do Google or other unknown app developers.
Why does the Microsoft SwiftKey keyboard need full access?