Zombified piglins that spawn riding striders no longer despawn. Walking logic was changed significantly. Player can now "safely" dismount, by looking at the block they want to dismount onto before dismounting.

Do Striders Despawn?

Dust Striders will despawn if the player gets too far away from them, or if the difficulty is set to Peaceful.

How do you stop striders from Despawning?

To control Striders, players will need a Warped Fungus on a Stick, which is similar to the Carrot on a Stick that is used to control pigs. Since they are a passive mob, Striders will flee when attacked.