Update 2/28/20: Some people in the comments are reporting unlocking this on their first attempt with no issues, so it may now be fixed. Leaving earlier tips below just in case.
This is currently a buggy achievement and is not unlocking when meeting the criteria. The following might help force it to unlock:
- Hard resetting your console.
- "Delete the reserved save space for FH4 under manager game and it popped in my first game afterwards where I met the requirements." - thanks @KabuKiArcade
- It's possible it may unlock if you reach the smallest circle and the final showdown begins immediately (vs. reaching the smallest circle but waiting on other cars to be eliminated still). This is how I finally got it.There has been some concern about how difficult this achievement will be to unlock, and whether it would be too heavily luck or skill based. While skill and luck will certainly help, this is not as hard as it seems. It may actually be harder to win the Eliminator, compared to this one.
This achievement *should* unlock if you make it to the Final Showdown in a level 1 car. That means no car drop pickups, and if you do enter any head-to-heads, you must not only win, but also keep your current level 1 car. So do not take your opponents car
, or the next level up car
.
You must select 
.
The Final Showdown will trigger after the last circle closes and you have no more than 12 drivers left. A 30 second countdown will be announced. Head-to-heads are disabled at this point, so you should be safe for the achievement.
A strategy I used that worked first time round was to hug the edge of the circle (remembering to move in each time of course), and keep a healthy distance from other drivers. Look for the white arrows on your radar and be ready to move away from them if pink dots appear. It's also helpful to know that if you stop moving, you disappear off other player's radars. This can be good for laying low if you're within the circle, especially if you can hide among buildings too to keep out of visual sight. Keeping distance from roads is also advisable, as every head-to-head will end on a road. By staying away from these, you'll minimize the chance of drivers challenging you immediately after finishing a previous race, especially in the last couple of circles where you have less areas to hide.