On a Pi 5 the Linux framebuffer comes up in 32 bit mode, but on a Pi 3B it’s coming up in 16 bit mode. The 32 mode looks quite a bit smoother (I’d love to know why - is it really just one extra bit on red and blue?).
My problem is I can’t get the Pi 3B to come up in 32 bit mode, even setting the kernel command line “video=” parameter. Both are running 64 bit Bookworm, and I upgrade fairly frequently.
BTW the Hyperpixel 4 is absolutely awesome! Unlike the mini TFTs over SPI, it works with the KMS drivers (testing kmscube and my own start on kms code) and runs fully accelerated!