Since i use metamask years ago, i don't have to set up a wallet?
If you have the wallet install and you have not deleted it, not need to setup the wallet again. But if you do not have Metamask again, you will need to setup the wallet again if you have your seed phrase backup, you have not problem.
Firstly meta mask is not a safe wallet will advice you to kindly sweep your funds from both of them.
You can move the eth to a new mycelium wallet mycelium supports eth and Bitcoin.
why is not safe?
anyways, i want to keep my eth/tokens on trezor, is it possible to connect trezor with mycelium?
Because Metamask is not an open source wallet. I am not also a Mycelium wallet user, but I saw on Mycelium that you can connect it to a hardware wallet.m, but just that Metamask is supporting more coins and tokens. Any close source wallet is not safe and secure to use because you do not know if the code used to build the wallet has some vulnerabilities like spyware and malware that can render your coins stolen.