Instead of downgrading, I would suggest you instead configure your Pi to boot the earlier kernel (5.15.0-1049-raspi), which is still on the system. In this way, you don’t mess up any future kernel upgrades (when the smb issue is fixed).
On the Pi, the kernel files are located in /boot, but the files actually used for booting are inside /boot/firmware.
To boot another kernel, simply replace the files /boot/firmware/initrd.img and /boot/firmware/vmlinuz with the preferred version from /boot:
sudo cp /boot/vmlinuz-5.15.0-1049-raspi /boot/firmware/vmlinuz
sudo cp /boot/initrd.img-5.15.0-1049-raspi /boot/firmware/initrd.img
sudo chmod +rx /boot/firmware/vmlinuz /boot/firmware/initrd.img
To revert back to the current kernel run:
sudo cp /boot/vmlinuz-5.15.0-1050-raspi /boot/firmware/vmlinuz
sudo cp /boot/initrd.img-5.15.0-1050-raspi /boot/firmware/initrd.img
sudo chmod +rx /boot/firmware/vmlinuz /boot/firmware/initrd.img
When a new kernel becomes available with apt, the files will be overwritten as part of the kernel package’s post-install script.
Based on the information from this answer.