CockroachDB, I heard the dev experience of spinning up nodes can be dumbed down to 1 or 2 docker commands, and it's Postgres compatible, continues to have global transactions, although you wont get the same transaction performance as something GPS/clock hardware synced like Spanner, it's still a good self hosted solution.

If you're interested, CRDB writes a lot about how they do their transactions on their blog, it's good to know what guarantees you actually get with your DB's transactions.