GL.Inet routers (based on OpenWRT) have an Allowlist Mode, where any unrecognized MAC address is denied network access by default until you manually switch it to allowed. But once unblocked, it gets unrestricted outbound access. I'm not aware of any uBlock-like functionality or crowdsourced list. But this doesn't make sense in the first place, since this traffic would be encrypted and you have no way to tell if it's nefarious activity or legitimate, unless you root or hack the IoT device in question and install an MITM certificate. But even then, both the nefarious traffic and legitimate traffic could be sent to the same https endpoint, so you wouldn't have any way to block it unless you disable such nefarious activity on the device itself.

So the best option would be to just keep the machine blocked, or limit it to an "IoT" VLAN that doesn't have Internet connectivity. And if the dishwasher needs the Internet to simply work, get rid of it.