Steps to perform after power cut to mac

If the power is interrupted to mac, what steps, if any, should be performed, even if startup appears fine.

Such as entering recovery mode, running First Aid Disk Utility?

As far as I know nothing.

Journaled file systems do not usually lose data when they are shut down unexpectedly, the journal maintains the consistency of the filesystem. Data that was being written right at the power loss may be gone. The actual file data does also depend on how the app writes data back, if it updates a file in place then the update might not be complete and so you have an incorrect file which you will have to check manually, if the app uses a safe save mechanism ie write to a temporary file and then move that to your file then that should be consistent but might be an older version. So you will need to check at the app level. Some apps will be able to recover better than others. For others you will have to look at backups.

I think disks are the only part of the system that have different behaviour between and expected shutdown e.g. by /sbin/shutdown or one by power loss,

Unjournaled file systems can lose data much more easily and that is why you should check the filesystem, the main example of this is filesystems using a form of MSDOS FAT or old Unix filesystems. Nowadays you should onlyu see these on Flash drives or other drives used for moving data between systems and devices.