Any Reliable Google Maps Ranking Techniques (getting to Local Pack in SERP)?

What can be done to boost Google Maps Ranking besides typical GMB page optimization?
Company have only 1 physical location. We added almost every possible bit of info that one can do on GMB. Every day posts seems doesn't do much either.

Do someone know a reliable and possibly guaranteed way to get to Local Pack in SERP?
* top 3 for the whole city: Las Vegas
** top 5-10 for the whole city while searching on maps

Currently we are in top positions only when search was performed in close proximity to physical location of the business.

Is there any way to do it in a relatively short period of time and with relatively low budget?