To expand on what Claudio has said, while TestComplete and TestLeft are based on the same object recognition engine, that's as far as the similarities go.
TestComplete is a complete solution for testing Desktop, Web or Mobile applications, manage object mappings, group codeless and scripted tests for execution and reporting, and integrates with a number of 3rd party technologies, e.g. Git, Jira, Azure DevOps etc.
TestLeft is a toolkit to allow you to identify objects in your application, using the Object spy to point at them, and generate an object reference for Java or .NET. That's it.
It's great for teams or individuals who are already managing their own visual object hierarchies, or have mature .NET or Java automated test frameworks in play, and don't want to acquire a tool that handles a lot of the work automatically.
Hope that clarifies.