I've also tested the newest Raspberry Pi OS (64 bits) that came with kernel 5.15.32-v8+ #1538. It works as expected (4 raspberries at top, messages, ...) and show the simple-framebuffer messages in the dmesg so I think it's using a non module simplefb.
Maybe the Raspberry OS developers faced this problem (or another) and revert back that change in their 5.15 kernel.
I've also tested the newest Raspberry Pi OS (64 bits) that came with kernel 5.15.32-v8+ #1538. It works as expected (4 raspberries at top, messages, ...) and show the simple-framebuffer messages in the dmesg so I think it's using a non module simplefb.
Maybe the Raspberry OS developers faced this problem (or another) and revert back that change in their 5.15 kernel.