Google sets a deadline for 100% mobile first in March 2021 due to COVID This is what Google sets when it will check your site to change it from desktop to mobile first:
Robots meta tags on mobile
Lazy loading on mobile
It will check which pages or sections of your site you are blocking.

Check the images and videos on your website. The quality of the images. If they are using different URLs on desktop than on mobile, if they are using different URLs on desktop than on mobile, Schema markup for Videos and where they are located

Bing submission Plugin:

Now we can index our content faster in Bing. And it has the official support of the Bing team. It will ask for an API that we get from Bing Webmasters. We can configure the plugin to do the automatic indexing.

We can see the publication on Bing's twitter.

Duplicate Content when migrating from one site to another: John Muller said there is no problem with this. Which also opens the door here to using expired content to use on your websites.

Google gives a lot of importance/weight to the exact name we put in Google My Business to show it in searches, Danny Sullivan says they are already looking at this and will fix it soon. Ex:

Finally the new Google podcast. Where John Muller talks about the factors to rank your site.