What is wrong with this datapack?

Hi, I've created a simple datapack for minecraft version 1.19.3 that gives all players the speed effect and also types a welcome message in chat upon loading. When i put this datapack into the datapacks folder of a world, load the world and type /reload in chat, nothing happens. I do not receive the speed effect, and the welcome message isn't shown. Why is this? What have i done wrong? I couldn't link the datapack to this post, so I've summarised it below:

Everything is stored inside a folder called datapack111
Inside datapack111, there is a file called pack.mcmeta. Its contents are:

    "pack": {
        "pack_format": 10,
        "description": "For use in superflat survival"
    }
}```
- Inside datapack111, there is a folder called data.
- Inside data there are two folders: 'minecraft' and '1A2B3C'.
- Inside 1A2B3C there is a folder called functions, inside of which there are two files: load.mcfunction and tick.mcfunction.

- Contents of load.mcfunction:
```tellraw @a {"text":"Datapack is working!"}```

- Contents of tick.mcfunction:
```effect give @a minecraft:speed 999 99 true```

- Inside the 'minecraft' folder there is a 'tags' folder, inside of which there is a 'functions' folder.
- Inside the 'functions' folder there are two files, called load.json and tick.json.

- Contents of load.json:
```{
  "values": [
    "1A2B3C:load"
  ]
}```

- Contents of tick.json: 
```{
  "values": [
    "1A2B3C:tick"
  ]
}```