> the pop-up will appear *even when* Microsoft Edge is the default browser
"Even when" says to me that this scenario is in addition to some other scenario, which must inevitably be when Edge isn't the default browser.
This is how the first sentence should read with correct parenthesization: "It’s worth noting that the pop-up will appear even (when Microsoft Edge is the default browser AND you’ve already pinned sites to the taskbar)"
> "the pop-up will appear even when Microsoft Edge is the default browser... The company is not targeting people who use Google Chrome and Firefox as default browsers."
Translation: it will show up for everyone, not just for Chrome and Firefox users.
The former part seems to imply to me that you get this suggestion even if you've already used the feature.
No. It says that Chrome and Firefox users are not specifically targeted, it says nothing about then not getting the suggestions when they are a part of wider group, like Windows users.