What is the ruling on omitting the Duha prayer for someone who is engaged in strenuous work and cannot consistently observe it?

It is permissible to omit the Duha prayer for someone who works in a strenuous job or for another reason, as it is a sunnah (non-obligatory) prayer. A person who performs a sunnah act is rewarded, though someone who refrains from it is not punished.

And Allah the Almighty knows best.