Tides on Fraser Island

Tide height is average for that area.

Give it a rest for 3-4 hours around the high and you won't have any stress.

You'll be able to drive fairly large sections nearer the high tide only to get to a pinch point further up the beach and be stuck with a good possibility of getting a salt water wash off on the wheels and underneath while you make your retreat.

Drive the beach early, go inland for lunch and daytrips, then drive back in the arvo. Not such a terrible tide scenario.

We will be at fraser at the same time,as far as i can see peak tide is 1.82m at 5.11pm 5/9 not 3 metres.
All the best

Typically high tide on Fraser is just a nuisance for most of the beach rather than something that would stop you completely. BUT ... Eli Creek is likely to be very difficult or impassable on most high tides.
Also any sort of swell or large seas will most definitely compound the issue and may make it impossible to travel along large sections of the beach especially north of Dundubara.
The other thing to consider is that even if you can get along ok at high tide you're likely to be stuck in some soft sand at the top of the beach making progress slow and fuel use extremely high.