Ok, since we are currently on the topic of off-topic, in my opinion, digitalization should look like this: every German citizen should have an online account with the tax office, to which employers automatically send all wage and income data, and other relevant tax data from banks, etc. should also be reported there. On this online account, you can then retrieve all documents such as pay slips at any time. Of course, the tax office or other authorities that need the information for something would also have access.
This would make many things unnecessary (e.g., tax returns, printing of pay slips, ...) and simplify some things. But I cannot imagine that I will still experience this.
There are already corresponding services like VaSt, for example. Otherwise, your outlined approach (all documents in one place) is not a desirable state, since basic principles of data protection cannot be maintained, e.g., the need-to-know principle for interested parties, which is not only required in the GDPR. "Documents" are also for humans. Digitally, this data can be used very unfavorably.
But this is slowly going too far here :)