There is an easy solution and I don't know why so many companies can't understand this. It's simple, pay a fair amount and there will be lower turn over. Every employee should be evaluated every two years so that their salary is at least the market median. And a raise doesn't even have to match what an employee would get from switching jobs. For example, if an employee could get 10k raise by changing jobs, many would stay if given a raise half of that. The reason is, switching jobs is risky. Next job could have a bad boss, bad coworkers, etc. If offered, it would often make sense to stay at a good job and take the 5k instead of going for the 10k with unknown risks.

But instead they just give no raises, or even insult their high performers with a "generous" 3% and cause resentment and lower morale.