Multiple service architecture

I'm developing an integration that will need at least 3 services, 1 as a main project with database and external access and other 2 to execute different heavy task, which i was trying to use http or rabbitMQ to communicate between those.
we`ll use Quarkus.
But as we were thinking about that architecture we realize that we are not doing the right thing ( at least it feels like that ), how would you do this?
What would you use to communicate between the services?
Should we use rabbit? should we use redis?
Keep in mind that put all of this in one service isnt possible because of scalability, also keep in mind that we dont know that much about architecture and only know the stack and services we already maintain, our team is new and everybody is trying to learn.