Nintendo has just published its Corporate Management Policy Briefing for this financial year, and included in its many pages is a reference to the company's next hardware platform. If you're expecting massive surprises at this point, then you might want to navigate away from this page.
In the document, Nintendo president Shuntaro Furukawa talks about the "Future Outlook" for Nintendo's hardware, and confirms that the next system will continue to use the integrated hardware-software approach that has been common with past consoles, like the Wii, DS and Switch.
Furukawa also helpfully confirmed that this new system will be coming in "20XX" and will continue to use Nintendo Accounts.
According to Furukawa, "Nintendo still plans to expand its business around the creation of unique integrated hardware-software products" and that "by creating a positive cycle" with its services and content using this approach, hopes Nintendo can "create positive long-term relationships and increase our points of contact with even more customers."
You can view the relevant slides from the presentation below.