I came to the same approach in a past job. One minor problem was that some functionality of that monolith was based on keeping big chunks of DB in memory. So o

I came to the same approach in a past job. One minor problem was that some functionality of that monolith was based on keeping big chunks of DB in memory. So on separated workloads, the instances dedicated to serve other functions, were keeping unnecessary data in memory, putting unneeded load on DB during startup. This could be solved by introducing some startup parameters. But for beginning this problem can be ignored.