In KDT functionality, this is what the "if object" operation can be used for... to check for an object to exist within a particular time range. Use the "if object" operation on your object to detect "Exists" not equal to true. Then right click on the operation and set the Auto-Wait timeout to the maximum time you want to wait. Then, add code that will execute when it comes back false to throw an error or something.
The effect of this is that the test will wait up to that maximum time for the object to Exist. If it doesn't within that time, you'll log an error. If it does, your test will proceed.
If, however, you are using Script code, I'd suggest using the methodology of WaitNNN methods (https://support.smartbear.com/testcomplete/docs/app-objects/common-tasks/waiting-process-or-window-activation.html#using-waitnnn-methods).