I reinstalled it last night.

It requires a legacy wallet created in bitcoin-core to serve as an rpc bridge to get onboard the full node.
If the wallet is not a legacy one, then comes the "Only legacy wallets are supported by this command" things when EPS fails to start.

However legacy wallets can't be created in bitcoin-core v26 the latest version neitherby GUI nor commandline nowadays.
I need to add deprecatedrpc=create_bdb in bitcoin.conf at first, then manually create a legacy wallet through commandline.

This whole process above reminds me that EPS is out of date. Time to move on to other substitutions maybe.