What I've done in these cases is keep the tx database ~3NF and denormalized at some interval to a reporting database [1]. That seems to be a fairly standard way

What I've done in these cases is keep the tx database ~3NF and denormalized at some interval to a reporting database [1]. That seems to be a fairly standard way to do things up to a point. [1] How data gets to the reporting database is implementation specific. Simplest case is run a nightly job to copy the data over. More complex cases use things like data lakes and/or event buses where all interested parties subscribe to data they want. I'm sure there are many others.