Writing something then immediately read when using read/write split: how to deal with replication lag
We have an issue where we write to the master table, then immediately must read ...


If the Requirement is that the read is time-critical and must have the very latest data, then read the very latest data - from the master.
This is especially true if you're generating values as part of the update and need to retrieve them, which you should ideally do within the same transaction.  (Actually, that's about the only reason I can think of that you'd need to read back the [same] data that you've just saved).