

My guess would be hotend not feeling so good. Those white spots look like result of temperature changes.
If you can read hotend thermistor data somehow (OctoPrint, for example, shows a chart for that) and see lots of sudden ±2-5°C changes - that’d be it.

There are more recent devices from Jolla, Finnish company. The only problem is the price, roughly the same as basic iPhone 17 (≈700€).