100 locations? Are you a franchise or a large brand?  When I see this type of question the first thing that comes to mind is to be very mindful of the guidelines. Not saying you are doing this, but you cannot use employee homes for listings or virtual offices.

Ok, so assumptions aside.

If you are truly in the guidelines legally and location wise then BrandA” vs. “BrandA” - Brooklyn Office is the way to go, adding a city descriptor is against the guideline unless that is how you represent your business in the real world.

You can use labels to differentiate them in the dashboard.

But really, read the guidelines closely, you could end up ina very bad place, Guidelines for representing your business on Google

Hope that helps

So there are a few points to clarify here.

1. You cannot report spam on social to GMB anymore.
2. Your Local Guide level will not impact your results, it is all about the quality of edits. (look at your ratio of applied/not applied)
3. The turnaround on sam removal is 1 -2 weeks. Anything not removed has been either missed or deemed valid. (Submit it again)
4. You can't submit spam to the GMB community, it will be removed due to privacy concerns.

Check out this article I wrote on getting stellar results from spam fighting https://www.brightlocal.com/blog/how-to-use-googles-spam-redressal-form-to-level-the-local-playing-field/

I would like to add, that I completely KW stuffing is not a good idea at all.

Adding a city name will not really help you, adding a service type might. BUT, this is all very risky.

Additionally, if you consistently are getting your name edited to what it reflects in the real world (As a TC I check the Secretary of State and the Street View) , there is a limit to the number of times a listing can be corrected before a suspension happens.

In some cases, you may also end up with a hard suspension. (Especially if a TC gets involved.)

Play by the rules, and make edits to competitors as Miriam suggested. Also, if you do the legwork report competitors that are using Virtual Offices/PO Boxes in the advertiser forums.