I think one reason why this is difficult for companies that are hiring software engineers, is that they can hire at multiple levels of experience. They just need good developers! A company that needs, say, a Golang developer, or Scala, or React, might be willing to hire a junior, mid-level or senior developer- they'll take whatever experience level they can get. Remember, saying that you don't want to hire someone to…
Companies usually just post multiple ads if they are hiring for junior or senior roles.
I don't think a job posting for both junior and senior developers would be appealing to a senior developer.
I think the market in Austria is different. If your job ad isn't compelling enough, you won't get any applications.