You need to make your mind first, whether you want to "scale up" which means to split the processing between different servers, or you are not even sure yet, whether adding different instances is a good thing at all.
Generally scaling up a web application indeed means providing dedicated hardware for the every major service involved. For your setup I'd make it four different servers
- PHP/Nginx instance
- database backend dedicated for Postgres
- column database backend to host Clickhouse
- processing backend to host rabbitmq and Golang microsevices
The good thing, each of those can be easily scaled up in turn by simply adding more instances of the kind (I am not sure how it's done for Clickhouse tho).
But I have a feeling that you are probably confusing the scaling up with just performance optimization. And you need to start from the latter. Simply checking the CPU load is tоo rough a measurement. You need a full qualified profiling to pinpoint certain bottlenecks.
From such incomplete data I can only guess that Laravel configuration is not quite optimal. 75 rps shouldn't be a problem for such a hardware. Make sure you have all production environment settings configured properly - all caching is turned on, etc. Also, switching to 7.4 and preloading could also help.
