If the 1 litre of new CVT fluid helped then your CVT fluid is completely worn out. If you feel this
pull - pull - pull - in high frequency at 35-45 km/h - its supposed to feel like a slipped clutch manual transmission when accelerating.
then the torque converter lockup clutch is chattering. The CVT fluid additives are supposed to take of this and lockup in CVT occurs very early to maximise fuel efficiency.
the particles on the magnet are clutch dust and burnt oil along with normal wear of parts.
The price of a fresh CVT unit is nearly Rs 350,000/- you can get a mechanic to rebuild it for you but make sure to use 100% new genuine parts (soft ones like clutches and seals) - the cvt pulley stack and chain is also considered wear part and can cause noise if extremely worn out. I have never seen it but have heard of it from some rebuilders I know. OTOH I have seen broken chains of Honda city gearboxes due to cooling failure or wrong oil choice, btw Honda CVT is the worst CVT fluid in the world just like their ATFs (useless)
all in all - this is all normal ownership cost of such a car - its a JDM import meaning no local technical support and no guarantee of availability of parts.