In the latest snapshot (22w17a) the warden's ranged attack always deals 10 damage, no matter the difficulty, this is different than the last snapshot.

How to reproduce: 

1. Switch the difficulty to easy.

2. Summon a warden, make it angry to yourself and pillar up 5 blocks so it can't reach you.

3. Wait 5 seconds for the warden to attack you with its ranged attack.

4. Repeat the above steps for the normal and hard difficulties.