Bitcoins scaling problem was solved by removing PoW/PoS and by removing the incentive structure (block rewards).
As soon as this is gone there was no reason anymore why it would not scale like similar systems. Its basically limited only by how fast data can propagate trough the network.
PoW/PoS was replaced by FBA (Federated Byzantine Agreement)
Its not a coin its technology used by several systems and based on BFT (which is way older than bitcoin and bitcoin actually is based on BFT as well although maybe unintentional).
FBA just adds the federated part so a decentral system can be build. While bitcoin instead used a work-reward lottery system (PoW) to decide who can write the next block rather than finding a block everyone agrees on.
Its really not that hard to figure out which of these solutions probably works better and scales somewhat like a distributes system is expected to scale.
PoW/PoS was replaced by FBA (Federated Byzantine Agreement) Its not a coin its technology used by several systems and based on BFT (which is way older than bitcoin and bitcoin actually is based on BFT as well although maybe unintentional).
FBA just adds the federated part so a decentral system can be build. While bitcoin instead used a work-reward lottery system (PoW) to decide who can write the next block rather than finding a block everyone agrees on. Its really not that hard to figure out which of these solutions probably works better and scales somewhat like a distributes system is expected to scale.