I started working in automation development with selenium and am told it is a hot field and can earn some high-end coding salaries. We recently hired a new manager who once hired immediately took us off of that to do the dev's unit testing until it is 100% code coverage. I'm worried, among other issues with that strategy, that I will not return to automation I will be stuck. How much more value is automation vs unit testing career wise? Is this a regressive move professionally?
Test automation is not high-end coding. You will not become wealthy doing either test automation or unit testing.
Typically, unit-testing is not a separate job title. Experience with unit testing is more likely to lead to a career as a developer than Selenium automation. You are likely to make more money as a developer than as a tester.