I have experience with GMAT Club Focus tests. They are worthy of accelerated test environment preparation. The tests were adaptive and conducted with the same Official GMAT exam-like interface. They got some selective questions from all the difficulty levels and are similar to the OG.
These tests would give an experience of timed solving and exam-like feeling. They even present a detailed score report for the test takers to identify where we have gone wrong and also provide solutions to the problems asked in the test. You can pause the test if you want a break, unlike the original exam which you couldn't do in the real exam but take one 10-minute optional break between any of the sections of your choice.
Try GMAT CLUB FOCUS TESTS!