Do the Salmon Run enemies get harder with each round?

Under the same conditions (without events), are enemies harder in round 3 than in round 1?

Do enemies in round 3 take a few more hits? Are there more enemy bosses? Or are different rounds (excluding events) the same?

It is only the paycheck of the workers that influence how the difficulty is. Ex: If you are a Part-Timer then the rounds will be easier then if you were a Trainee. If you survive until the next round then the boss salmonoids will despawn. The difficulty between rounds is always the same unless a player messes it up.

Edit: The difficulty between round is random because of events Ex: One round is High tide, Round 2 is The Griller And round 3 is Cohock Charge.