I agree that they definitely should not announce a successor this year especially if it is not releasing until next year. If anything, maybe a price cut on all Switch models this year could be an option.
I also agree that they don't need a year plus between reveal and release. Those days are over. Switch still has software pulling in big numbers, with Splatoon 3, SV & TOTK all breaking various records. No Nintendo system besides Game Boy with RGBY ever had that much record breaking this late in its life. The DS did have BW but that wound up being the lowest selling generation starter (probably because the 3DS was announced too early imo).
They probably announce it before next year's FY Earning Release in May (in order to factor it into their forecast). April reveal, blow the lid off around June/July and then release in September. Basically the same timeframe as the Switch if we exclude the "special case" of it being announced early.
