This is not guaranteed at all. I read articles in the past mentioning that you will see "trains" of dozens of white dots one behind another in the sky.
Do we currently see satellites in a dark summer night? Yes. So for Starlink it will be the same, except with 10 of them one behind another.
I'd be happy to read more sources confirming or infirming this.
"Will" there means "right after launch, when they're in a very different orbit from final". They spread out by a very large distance, so that in the final version you'd only have line of sight to a few scattered across the sky.
Here's a study https://arxiv.org/abs/2101.00374 that looks at Starlink satellites with the visor. Looks like Starlink will be visible only in rather dark areas with good viewing conditions. It's not like you're just looking up and they will bother you.
Regarding the satellites, i hope the Starlink satellites will also be not visible to the naked eye once they reach their final orbit now that they have the sunshade.
On the other hand, these technologies provide a huge benefit to the people on the ground.
If you want to complain about Loon you should also complain about regular airplanes, helicopters, zeppelins, weather balloons and balloons in general.