Indicates that the device is under heavy interrupt load.
Caused by IRQs coming in faster than the system can handle them.
They are queued for later processing by ksoftirqd.
Run...
cat /proc/interrupts
... and post the results.
Your device target is ramips/mt7621, which is a DSA device.
Even though the EA7300 has 2 CPUs, only one is being used for DSA devices in 21.02.
I suspect the best option is to roll back to 19.07.n, until the issue is fixed.