It might not be necessary to replace hardware here. Can you please get a screenshot of the WebUI for Nucleus? I’m seeing some crashes but it’s nothing apparent as the problem.
Next step (regardless of what your screenshot shows) is to remove your databases from the equation and see what happens. Here are the steps. Please don’t reimport your databases until you’ve had plenty of time to determine if the problem persists.
I have one more thing I’d like you to look at if you don’t mind. I am seeing network errors in connecting to Roon servers, time servers, and a NAS that seems to be a part of your setup (//SYNO220/homes).
If you go back to the WebUI you shared with me, change the DNS server to 184.108.40.206 or 220.127.116.11. This is also a change you can make on your router if you feel confident enough in doing so.
It just seems like the Nucleus is going off the network rather than experiencing a hardware problem (unless it’s the network interface of course).
If you can, try this in the next few hours and I will do my best to get back to you before the weekend.