I wonder about Nintendo and Nvidia. The Tegra chip powering the Switch was pretty much Nvidia’s last shot at mobile chips. Everything they have now, and in the announced future, is geared towards different markets. I’m sure Nvidia could make a great mobile chip again, but I don’t think they want to divert the resources required. It really makes me wonder about backwards compatibility, and future hardware for a Switch 2.
I don't think nVidia is ruled out, but the Tegra is ARM. That means any other ARM implementation like Exynos or Snapdragon should allow backwards compatibility.