Comment by Nextgrid
You can still horizontally scale a monolith and distribute requests equally or route certain requests to certain instances; the only downside is that those instances would technically waste a few hundred MBs of RAM holding code for endpoints they will never serve; however RAM is cheap compared to the labor cost of a microservices environment.
For those numbers, yeah you should absolutely do that. But you might want to host your database on different machines than your application because the numbers will likely differ by much more than a few hundred MBs.