It's not a BotW situation because the same game cartridge will work on both systems. Nobody is going to feel cheated for buying Metroid Prime 4, the critical darling of holiday 2024, when a next-Gen patch (or even nominal upgrade fee) is revealed half a year later. Compare to BotW when you would have had to pay $60 twice. If anything you get an easy bump in word of mouth since people will be talking about your game again half a year later.
The value of Switch 2 enhancements is actually greater if it's already established that Metroid Prime 4 is already a good looking game on Switch, but looks even better on Switch 2. Potential Switch 2 customers who already have a large Switch library can see the obvious and immediate value of upgrading to Switch 2, even if they aren't interested in buying many brand new Switch 2-exclusive games at the moment.
If you delay Metroid Prime 4 for six months, you are losing this benefit and making faithful Switch owners who faithfully waited 7 years for the Metroid Prime 4 they were promised feel cheated. And there are a lot of those Switch owners, compared to the relatively few Wii U owners. You are losing goodwill, losing a potential critical and sales smash hit for 2024, losing the impact of the "wow" factor when a already great looking game suddenly looks better for no/minimal cost, and gaining nothing.
I totally understand looking to the Switch launch for the Switch 2, that's how I knew Switch 2 would be spring 2025 at the earliest. But if Switch 2 is backwards compatible, you should be looking not to the Switch launch but the PS5 launch in terms of software. In this case there is no benefit to delaying for "cross gen".
The only exception is if Metroid Prime 4 still isn't close to being finished. Nintendo choosing to release Prime Remastered after sitting on it for over a year tells me that the game is almost done.