If you're willing to keep an open mind, try poaching someone from a non-tech company that wants to jump ship. There are an increasing number of such people.

They likely are getting underpaid compared to their peers at a tech company.

The downside is, a "senior software engineer" at a non-tech company might not be quite the same level as a "senior software engineer" at a tech company. I say this as one of the former myself.