Microsoft does not preinstall third party bloatware, that's OEMs running on thin margins. There have been Microsoft efforts to share with OEMs the effect of bloatware on boot times and incentivizing boot time reduction.
Yes they do. My Windows 10 upgrade, which was from Microsoft, came with Candy Crush [1] and some third party PDF annotation app. They also added ads in their OS [2] to try and upsell you.
[1]https://www.theverge.com/2015/5/14/8606925/candy-crush-saga-...
[2]https://www.theverge.com/2017/3/17/14956540/microsoft-window...