All entities despawning

All of the mobs despawn, regardless of status. If you feed them, tame them, walk away for two minutes, less than 20 blocks of space to go, they despawn. This is very frustrating because this issue has been “resolved” several times yet nothing has been changed. This issue is an easy fix yet nothing is being done. This is also frustrating because people work hard and mobs like villagers sometimes can not be replaced easily. I’ve stopped playing the game several times due to this issue. This! Is! Important! Do not skip this, it is an urgent issue that NEEDS to be fixed, as it makes the game very unfair and sometimes unplayable. I even had a horse, it had a saddle and diamond horse armor. I turned around and turned back and it despawed just like that! Very unfair. PLEASE FIX THIS. I’m not going to play until it’s fixed.