PoW is the right consensus for RVN.

PoW is a rigid consensus and that is exactly what is needed for RVN's use-case. Nothing can persuade it.

Nowadays, high scaleability seems to be a big deal but when it comes to security, it is highly recommended to prefer the most-durable tank over a high-speed car.

Yes, the high-speed car will deliver the goods fast but that car can be destroyed rather easily. The result is destroyed goods and wasted petrol and a broken car.

On the other hand, the most-durable tank is slow and requires lots of petrol to run in the long run but there is nothing that could stop it. It will deliver the goods. Brute force cannot stop it.

PoS scales to greater heights but PoW is nearly indestructable.

It is impossible to have both things. You must trade one for the other.