If it says the test is not timed then the amount of time you take bears no relevance at all. I don’t think they will even know how long you take either.
They recommend at least 75 minutes so that people do not underestimate how long it will take to fully complete the test and review answers before submitting.
The test should take 75 minutes or more to complete basically. That’s why for these tests you never have to request extra time.
Part of the reason these tests are not timed is to ensure fairness for people who are neurodivergent.
I remember asking the early careers team at HSF about this at an event and this is what they said.