throwaway063_1

How else should verification be handled?

Many European countries have secure electronic identifications that are trusted by the government, banks etc.

Linkedin could easily use this to verify the identities.

Example of services where you can verify the identity with 35 different providers using a single API:

https://www.signicat.com/products/identity-proofing/eid-hub or https://www.scrive.com/products/eid-hub

I doubt it would take more than a sprint to integrate with this or other services.

There are companies such as Signicat, Scrive and others that provide an API that integrates with different national authentication providers.

If you sign in with Google, the site knows your gmail address.

What about a hybrid approach?

You could use a managed db service as a live replica dedicated as a backup only. The queries would go to your local database on beefy hardware, while the replica would just have to be powerful enough to keep up with the WAL stream.

In fact a decent % of people stops shopping on your site if there's a few ms lag.

While it's still true, I have read that the accepted lag today is higher than 10-15 years ago, because they have lower expectations due to a general decline in page load speed. (React pages with spinners/placeholders, newsletter popups, higher page weights etc.)