I'm having issues with my 2 HomePod minis also. Worked great for a few weeks or so... now constant problems. They keep disconnecting from my wifi and HomeKit and will not setup properly. Now nothing! An Error Code 301003 comes up. I've been through all suggested solutions... first rebooting/re-starting everything. Then resetting the HomePod minis with no personalization. Then resetting the HomePod minis, wifi, bluetooth. Restarting my iPhone etc. Nothing. I now own 2 cool-looking paper weights that cost $99 each. I will abandon Apple HomeKit and move to other vendors and solutions... this is way too frustrating. I'm a former Apple employee (retail business team) and am proficient on Apple devices.