As always with lawyers, it depends.

In my opinion however, the general rule is that litigation is more stressful.

You're in a much more combative environment, which often translates to a toxic internal team culture.

Timelines are far more relevant and common, and the consequences of missing them are more dire.

Adding to the stress is the make or break, all-in mentality of litigation.

You will live in the office during trial / arbitration.

On the flip side, depending on the team corporate can be more stressful, a sort of slow burn, if you end up working on many transactions at the same time as there is no 'downtime between trials'. Just a never-ending churn of transactions. Also possible that corporate clients can be more demanding, and because timelines are set by clients instead of the court, they can be much more unreasonable.