MariaDB/MySQL: Dump current transaction data

Suppose, I have a transaction that contains some delete, insert and update queries with a lot of select-joins and values inferred from other tables. Sometimes even outright math inside queries. This makes forensics very hard, but reengineering the queries isn’t going to happen any time soon.

How can I, within the transaction, see (or, preferably, dump) the actual data (in tables and rows) that is being changed within the transaction before committing it?

In short, I want a transaction delta.

I use MariaDB 10.3.23