Hard to say but I wouldn't be surprised if they aren't.
I could see the Switch still getting supported with some lower tier cross gen games, as well as stuff they already promised for the OG Switch like Prime 4.
But I could see the big tentpole games like Mario Kart, 3D Mario, Animal Crossing, 3D Zelda, Pokemon, etc being exclusive.
They'll want people to upgrade, and Nintendo consoles are usually way more exclusive driven than other systems.
On the other hand though, not releasing something like Mario Kart 9 on Switch 1 is literally giving up several dozen million game sales. So it wouldn't be shocking if they do go with a cross gen model.