If there will be a Bitcoin 2.0 or a change of network from POW to POS then not only the network congestion is being fixed but many more, and also it can reduced the energy consumption.
I don't think Upgrading Bitcoin network into version 2.0 would solve these problems.
as you can see Ethereum Gas problem still there even after upgrading into 2.0 and becoming a POS.
other than that Ethereum have a Team behind, a group of developers. and Bitcoin is not controlled by anyone. I am not an expert, sorry if I am wrong but I think it is technically not possible to do that.
also what about all those miners who will go jobless after that?