The most important stamina asset is the well rested bonus. Plan your adventures around having it, and retreat to base to refresh it. Get into the habit of exploring at dawn, and retreating/portal to base in the evening. A high level rested bonus can last the entire day.

Parrying (super block) has a large stamina penalty. Upgrade the bronze buckler to an iron shield and use normal blocks.

Avoid sprinting. There are very few reasons to sprint against bonemass. Constant stamina stress such as jumping/dodging/bows will block stamina regen. Trust the power walk, standard movement can handle most threats.

Flatten the arena with a hoe before the fight, to eliminate water hazards and remove jump obstacles.

Power up with poison resistance. Tasty mead/stamina potions can be used in a pinch for fast stamina regen.

The iron mace is the choice weapon for the swamp. It has good handling and most swamp enemies are weak to it.