Local SEO wants to set up canonical tags on two blog articles naming the homepage as canonical. Will it work as they suggest?

The site in question has two blog articles that Google deems are targeting *keyword* (which is also targeted by the landing page & site in general)

The SEO agency proposes that if they set up a canonical tag on each pointing to our homepage, it tells Google that we want the homepage to rank for *keyword*, and *keyword* will improve in the Google rankings.

I haven't had much luck finding discussion of the technique on Google, though it sounds like this is a misuse of the tag that may have negative consequences for the indexing of the blog articles.

Is there a particular name to describe this use of canonical tags and is it accepted/valid?

(Apologies if this post doesn't fit well under this sub - recommendations of a more appropriate forum are welcome. )