Manually forcing reinstall of pfSense-kernel-pfSense-2.6.0.pkg should get you onto the correct kernel after a reboot. But the kernel file you have already looks correct.
Once you do that can you ever be 100% confident of the install?
If reinstalling is very inconvenient then it's probably worth trying first but reinstalling and restoring a config is usually quick and easy.
https://docs.netgate.com/pfsense/en/latest/backup/restore-during-install.html

Steve