I have yet to find one that allows you to partially commit a confirmed part of a transaction (newly finalized block) while leaving the rest (partially confirmed blocks) open.

This looks like it will support the blockchain's blocks and irreversible block to me: https://www.postgresql.org/docs/14/sql-savepoint.html .. It just does it on disk not RAM so not very useful for a very high volume L1, but still useful to learn the technique and useful for each app where full nodes can provide additional APIs. I just checked, because it is in CockroachDb too, it looks like this can work atomically in a cluster (multiple databases) without needing to hire a full time database admin (as postgres might require): https://www.cockroachlabs.com/docs/stable/savepoint.html#savepoints-for-nested-transactions .. I have not verified this, on my radar though.