Ring signatures have no effect on L2 usage, and key images are also not a problem at all here.
Monero can support L2 networks, it's just a bit more complex than Bitcoin:
But it is possible, and there are two new approaches I need to add there that will be very simple to implement after Monero implements the Seraphis upgrade that is being planned right now.
Monero with lightning will be unstoppable. :)