I am also not quite sure what to expect from Ethereum, not only in the near future but also in the long term one. I am not that deep into all the coding stuff and therefore i am no expert in what that merge really will bring execpt from the fact that Ethereum will no longer be a proof of work coin but a proof of stake coin then. I do think though that many users may have exaggerated expectations to that merge and what it will mean in regards to transfer fees on the ETH chain.
I can imagine that some people could sell off their ETH if they realise that the merge did not have the impact on the transfer fees that they would have expected.
On the other hand ETH is so big now that i think it is almost impossible that it will lose relevance and that it won't be a top 5 coin in a few years anymore or something like that.