My TS-453 Pro just died too (after 10 yrs 24/7) - the infamous Intel J1900 degradation issue!
I will attempt the 100 ohm resistor fix - but it is only a temporary fix.
After exchanging emails with NAS Compares, and speaking to QNAP UK Sales, I am having a TS-464 8G delivered tomorrow.
According to the QNAP migration tool, I should be able to just plug my HDDs into the new unit - having made sure that the new unit is updated with the latest firmware beforehand (before HDDs are inserted).
I also got assurance from QNAP UK Sales that, since Jan 2024, the memory in the 8G model can be upgraded.
Something to consider…