Bedrock Entity AI doesn't seem to work at all

I created a Bedrock entity in Blockbench with a custom model and texture (that I have working), but doesn't move or attack. I have looked at reordering/ simplifying the AI & goals prioritisation, but doesn't appear to change anything. Perhaps I need to set custom animations as well or disable animations entirely? Any ideas would be greatly appreciated.

The code (in case this helps)

griever.json:

{
  "format_version": "1.13.0",
  "minecraft:entity": {
    "description": {
      "identifier": "maze_runner_one:griever",
      "is_spawnable": false,
      "is_summonable": true,
      "is_experimental": false
    },
    "component_groups": {
      "maze_runner_one:griever": {}
    },
    "components": {
      "minecraft:nameable": {},
      "minecraft:type_family": {
        "family": [
          "maze_runner_one:griever",
          "griever",
          "mob",
          "monster"
        ]
      },
      "minecraft:loot": {
        "table": "loot_tables/entities/maze_runner_one_griever.json"
      },
      "minecraft:breathable": {
        "totalSupply": 15,
        "suffocateTime": 0
      },
      "minecraft:burns_in_daylight": {},
      "minecraft:collision_box": {
        "width": 1.4,
        "height": 0.9
      },
      "minecraft:health": {
        "value": 30,
        "max": 30
      },
      "minecraft:attack": {
        "damage": 5
      },
      "minecraft:movement": {
        "value": 0.4
      },
      "minecraft:navigation.walk": {
        "can_path_over_water": true
      },
      "minecraft:jump.static": {},
      "minecraft:physics": {},
      "minecraft:hurt_on_condition": {
        "damage_conditions": [
          {
            "filters": {
              "test": "in_lava",
              "subject": "self",
              "operator": "==",
              "value": true
            },
            "cause": "lava",
            "damage_per_tick": 4
          }
        ]
      },
      "minecraft:pushable": {
        "is_pushable": true,
        "is_pushable_by_piston": true
      },
      "minecraft:follow_range": {
        "value": 64
      }
    },
    "events": {}
  }
}

griever.entity.json:

{
  "format_version": "1.8.0",
  "minecraft:client_entity": {
    "description": {
      "identifier": "maze_runner_one:griever",
      "textures": {
        "default": "textures/entities/griever_texture.png"
      },
      "spawn_egg": {
        "base_color": "#009999",
        "overlay_color": "#990000"
      },
      "materials": {
        "default": "spider",
        "invisible": "spider_invisible"
      },
      "geometry": {
        "default": "geometry.griever"
      },
      "animations": {
        "default_leg_pose": "animation.spider.walk",
        "look_at_target": "animation.spider.walk",
        "walk": "animation.spider.walk"
      },
      "animation_controllers": [
        {
          "move": "controller.animation.spider.move"
        }
      ],
      "render_controllers": [
        "controller.render.spider"
      ]
    }
  }
}

maze_runner_one_griever.json:

{
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "item",
          "name": "minecraft:amethyst_shard",
          "weight": 1,
          "functions": []
        }
      ]
    }
  ]
}