I feel like this is common practice. Synergy between company’s product is very common. There are alternatives you can use instead of outlook (ex. thunderbird, mailbird, etc). If you don’t like Microsoft practices then you can opt out and find an alternative. But speaking on behalf of the less techy savvy consumer i would be pissed off about this.
+1 for bitwarden. I use the desktop app + browser extension + Android app. I have to manually hit the sync button on the android app every so often but other than that it just works.