Announcement incoming:
Quote Originally Posted by Bloomberg
Nintendo Co. plans to begin assembly of its new Switch as soon as July and release the upgraded replacement for its four-year-old game console in September or October, people familiar with the matter said.

The new console, likely to be priced higher than the $299 original, may be announced ahead of the E3 conference starting June 12 to allow publishers to showcase their full range of Switch games at the global event, the people said, asking not to be named because the plans are not yet public. It will be sold alongside the $199 Switch Lite, with the standard Switch phased out over time.

Assemblers will start shipping the new model -- whose commercial name is known only to a handful of people within the Kyoto-based company -- as early as July and production is planned to ramp up to a peak in the October-December quarter. This is despite widespread semiconductor shortages that have affected the supply of everything from automobiles to TVs, headphones and games consoles, including the Switch itself.
Nintendo Plans Upgraded Switch Replacement as Soon as September - Bloomberg
Quote Originally Posted by Eurogamer
Nintendo's long-awaited Switch upgrade is expected to be shown ahead of E3 2021, according to a report published by Bloomberg today and Eurogamer's own sources.

I understand this is to ensure third-parties working on games which support the upgraded Switch are free to announce these projects at E3, and before Nintendo's own digital showcase later in that week.
Nintendo Switch Pro reveal expected before E3 • Eurogamer.net