Unlike Google organic SEO, Google Business Profile doesn’t look at coding and backlinks to determine “relevance” thus increasing your positioning in search results. Rather, in the case of Google Business Profile, it is heavily reliant on EXACT data points you put on your Google Business Profile profile (official business name, address, phone number, etc.) and looks at third party sites the likes of Manta, Yext, InsiderPages, etc. to see if the exact same data exists on them. The more frequently data points match in terms of quality and quantity, the higher the potential for increasing your ranking within local search results for relevant terms.
There’s much more involved with Google Business Profile optimization, but the above covers the core foundational items needing to be addressed.