PhysiX vehicle does ray cast only downwards, so your suspension won’t react to vehicle being flipped. A lot of PhysiX vehicle have much bigger mass and very low center of gravity for stability, which again can be an issue and this is what makes them flip back to wheel easily.
I assume that you are targeting arcade style of gameplay so my suggestion would be to make your own vehicle component. It’s not hard, I did it myself with just blueprints for 10 wheeled vehicle with all wheels driving (check signature).
Two parts that you need is suspension and a bit of custom friction physics. I can explain how I’ve build them in my case and can tell you what works and what might not work or requires some C++ coding.