Should I finish the sections within the 35 minutes even if I have to guess on the ones I can’t finish and then just go back and review the ones I wasn’t sure untimed before I check the answers
Yes. It may be that you are taking a long time in part because you can. So force yourself to work under timed constraints. The best way to do this is with a full timed PrepTest. Once a section is done, move to the next (just like test day). Then go back later to finish your incomplete sections. Working through the test this way will provide with a sense of urgency, and that may be exactly what you need.