What happens in years to come when the supply reaches 144 Million? Does PoS stop?

good luck waiting for that to happen. also, transfer fees are a thing that exists
So... You're saying you don't know either?

i think you have severe issues with reading comprehension. as with any coin, when mining is over, in this case PoS rewards, nodes get coins from transfer fees. what isn't clear to you?
Nodes receiving transaction fees goes without saying.