If you want to download the Bitcoin Core wallet (which is not installed by default for obvious reasons) you need to first shutdown the node via the dashboard menu FIRST, then startup Bitcoin Core UI. The Bitcoin core wallet can not run/share the blockchain data at the same time as the node is running. If you are setting up the wallet for the first time, make sure you select /media/nvme/Bitcoin as the default folder otherwise it will start to download the blockchain on your SD card which will cause you lots of headaches (will fix this with symlinks in an update)