Not unless you enable it on you router, somehow. That’s called QOS and is generally not enabled by default.
Sure, no question about that. But it’s a pretty good indication of what your internet provider delivers vs. what it promises you.
At least half-a-dozen times, I noticed it didn’t deliver, rang and got back to acceptable levels of service. If you don’t test, you just don’t know, as any given download/upload is itself hugely impacted by the other party, while speedtests make sure you get the best possible counterpart.