there are several websites which appear to just not work as reliable as usual. twitter, udemy, fastmail among others.
Slower and less stable compared to what? When? Where? There is no "the internet" to measure latency or stability on. I haven't noticed anything today, but maybe if I lived in Beijing getting roasted by heat, or in Hanoi with electricity going on and off, or in Oklahoma with high winds and tornados I might have a different experience.
Or in Eastern Europe where half of Internets are blocked due to the anti-propaganda measures and half of Western services have stopped working in this area.