Delete memorized message suggestions

I have an iPhone 7S, software version 11.2.5

When I go to send a message and begin typing a name (or #), EVERY iteration of that name or number appears as a suggestion (including group texts that included that contact). In fact, the single contact of the person I want often appears at the very end, and sometimes NOT AT ALL! I often have to go to contacts and look up the person, and then tap message under their name to generate the ability to send a text.

A) is there a way to remove ALL past group texts from the "suggestion list?"

B) why isn't the initial suggestion the most intuitive single number as things were 6-9 months ago?

Thanks