It depends on the amount. If you have upwards of 20M sats of liquidity then I think it's worthwhile spending some money to have a raid setup with hard drives (or ssds), a UPS is a must, no matter what and an extra standby pi ready in case something goes wrong. I believe an RPi is really nice and sufficiently powerful device to run bitcoind and lnd, but please, DO NOT install anything else. I repeat, nothing else, if you are really serious. Bitcoind and lnd is enough load for the raspberry pi. I would suggest you keep your hands away from the "app store" that umbrel provides. At max you can install 2-3 more small tools like RTL/Thunderhub to manage your node. The lesser software bloat you have, the lower the attack surface and the better your Pi's fate - an unforeseen vulnerability in docker or npm, tor or any other piece of software could lead to bad situations where the attacker has control over your node, so keep the attack surface as low as possible. And even after all this, remember, it's not the hardware that might cause loss of funds but could be some nasty vulnerability in lnd. Remember it's still a beta software, let's not act like it's a super robust piece of software, and even though it's being used by so many users and companies, it is still prone to zero days and can result in loss of funds and the devs themselves mention:

Obviously this doesn't mean you don't explore it and utilize it; it's just a caution to keep in mind to make you more informed about the risks, so that you take good care and don't do reckless things with your node.