Hello there, Alexander.
I totally get that switching to the modern view in QuickBooks Online (QBO) can be tough, especially since a lot of users, including yourself, prefer the Classic View. I’ve got a workaround that should help you get what you need.
Intuit is moving everyone over to the "Modern View" (sometimes called "Enhanced Reports") as part of an update to make reporting smoother and easier to use. But right now, there’s no way to set Classic View as the default permanently.
As a workaround and since you’ve probably already done this, you can just click Switch to classic view whenever you run your Profit & Loss or Balance Sheet reports, or when you’re drilling down into transaction details.
Also, after switching to Classic View and customising your report (dates, columns, etc.), you can hit the Save customisation button at the upper right corner to save it as a custom report so it’s easier to access later.
Let me know if you need any more help with QBO. We’re here for you and want to make sure everything’s taken care of.