Your comment heavily implied (to me) scaling databases horizontally. Yes, it's not necessarily "Google scale" either, but it's a ton of extra complexity that I'm happy to avoid. But a Google employee is probably going to approach every public-facing project with the assumption of scaling everything horizontally.

With multiple servers talking to a single database, I'd still prefer to let the database handle generating IDs.

Yeah, there's too much advice jumping straight to uuid4 or 7 PKs for no particular reason. If you're doing a sharded DB, maybe, and even then it depends.

Speaking of Google, Spanner recommends uuid4, and specifically not any uuid that includes a timestamp at the start like uuid7.