The code definitely hasn’t been updated to support exiting yet, but I think it should be possible, with the caveat that withdrawing the Eth and RPL may be tricky.
First, you have to exit the validators, which you can hopefully do in the ‘staking brain’ UI. After they’re fully withdrawn, ie, their balance has been transfered into the minipool contracts (takes up to 8 days), you can use etherscan’s UI (by connecting your withdrawal address) to:
upgrade the minipool delegate, if not already on the latest version
call the distribute function on each minipool (you will need to be logged into etherscan with an email/password as well so you can use a custom abi), which will transfer the eth balance to your withdrawal address post-commission, and finalize each minipool
Finally, to withdraw the RPL, you will need to connect your node wallet to etherscan and call withdrawRPL on rocketNodeStaking. The input amount is in wei.
Similarly, if you have any unclaimed interval rewards, you can claim them from etherscan, but providing your merkle proof to do so is quite complicated, so best to make sure you claim everything via the UI first.
If this sounds daunting, it is probably better to pester the dappnode maintainers to add support to the dapp. If you need the funds urgently, swing by #support on the discord and someone may be able to help with the process.