Trading systems are complex distributed systems. They need extremely high reliability and low latency, on enormous transaction volume.
There are lots of complex failure modes in a system like this, and minimizing them is an advanced skill. The learning curve for a competent generalist senior engineer to get good at these kinds of problems is significant. Designing and implementing a national securities exchange is a big deal.
This is a place where you want either experienced developers who have worked on other stock exchanges, or at least FAANG engineers who've worked on systems with analogous challenges. This is not a place you want to skimp on salary.
You want HFT experts because this is the definition of an HFT system. Those salaries even in Australia start at $200k for a junior developer and go upwards quite quickly.
Of course OP thinks that $80k is a good salary for a developer so that ought to tell you how competent she is.
There are lots of complex failure modes in a system like this, and minimizing them is an advanced skill. The learning curve for a competent generalist senior engineer to get good at these kinds of problems is significant. Designing and implementing a national securities exchange is a big deal.
This is a place where you want either experienced developers who have worked on other stock exchanges, or at least FAANG engineers who've worked on systems with analogous challenges. This is not a place you want to skimp on salary.