Running Amazon Ads - Contract Out? Your Experience?

I’m prepared to invest a little money into book advertising again. Do you contract your advertising to anyone, particularly for Amazon Ads? If so, how well has it worked?

I’ve done these myself in the past. Predictably, it didn’t work, and I just burned a bunch of money. I’m familiar with how the ad platforms work; just don’t have the time/expertise to hammer out a decent ROI.