Litigation is far less forgiving than corp, so if you can't survive corp you probably can't survive liti either.

While hours can be bad in both, in corp you are basically paid to structure transactions and complete legal paperwork for the client so that they can person their business activities. Client is happy if it achieves its commercial objective without falling afoul of the law.

In liti something has gone wrong, there is a dispute, and you are paid to match wits with someone on the other side who is literally looking to tear down your client and your case at every opportunity. Usually it's zero sum and only one side can win, so 50% of the time you are losing and having to explain to the client why you lost. And you have to go to court and be scolded by judges/registrars if you screw up the procedure or the law.

Just from the nature of the work alone, you can see why one is more intellectually and psychologically demanding than the other.