It's actually very simple to read a journal to determine the full current state of the database. It's potentially even faster than parsing XML, yielding exactly the same in-memory structure. Your computer will do it faster than you can cancel the operation. This also gives you history for free, rather than as nested entries (though you might have to write a log flattener to prune old journal entries). The operations required to parse log entries like "icon 4 is now this data" and "entry 791 now uses icon 4" are minuscule. There is no complexity, no nightmare, no loss of relations.

I am not advocating for KeePass switching to a journal, however, because the current ecosystem is fine.