fuel odor in and under trunk

Rollover valve will not stop fumes.
An evap canister and all related components will solve most of your issue.
Not willing to add the necessary parts? Ventilate garage or park it outside.
I’m sure thats not what you want to hear (read) but i had the same issue with an off brand a few years ago,and fumes were really bad when driving. Especially with less than 1/2 a tank.