1. Search site.
As a separate product, it would need to earn money.
Improve filtering and the search itself.
It would be able to host ads from other advertising networks (like any other large site).
Make an additional API or tool to regularly update data by certain filters)
You can charge money for all these things.
2. Ads. As a separate advertising network, for which google.com will be just one platform/site, like thousands of others.
3. Mail as a separate service, leave the ability to log in to other sites through this account, so you keep one login for everything (who needs it).
It can also be an advertising platform for any advertising network. You can offer better services for a fee, while keeping the basic functionality free.
4. YouTube as a separate service, as well as a platform where many other advertising networks or advertisers will compete for advertising space. Introduce paid plans for creators, where there will be a certain volume limit after which you will need to pay for the service.
5. Cloud services. Separately.
6. Google Docs. As a separate online document service, you can charge a subscription fee for certain features as in 365.
7. Browser. No need for Manifest v3.
Improvements to the extension store.
You can also sell advertising space and make integrations with various tools, as Opera does, for example.
You can even make some kind of subscription, or make paid extensions that will speed up sites, improve the look, and cut out ads.
This is the first thing that came to mind. This can be thought out better.
This will create competition for other players and for these potentially divided campaigns.
General improvement of products. And all of this can be kept "under one login, in one ecosystem," with the ability to make "one system and one login" in conjunction with other tools.