Number of messages mqtt subscriber can process per second

We will have 10k devices which will publish the messages to a single mqtt. So generally, 10k messages per second will be published to a single topic. We have subscriber in java/spring-boot. I have read somewhere that subscriber can able to process at max 100 messages/second. If that is the case, then in order to support such scale we need to have 1k pods of this microservice and then use shared subscription which is not feasible. So I wanted to understand that does this number (100 message per second subscriber can process) is fixed or it is adjustable or is it dependent on other factor as well like the time required to process a single message etc.