I have followed every step to make the beacon work, yet it still not working.

1. Build Beacon Pyramid (I did minimum in my single player world and a full on my realm)
2. Select Buff(s)
3. Add E/I/D/G payment
4. Activate

I am getting the buff icon and timer but it is not effecting my mining at all, its the same with and without the buff.

I have never used a haste beacon before, I got it in my realms world and it did not work then in 1.15.1 or now in 1.15.2. Yet I know it should work as I have seen the hermits in hermitcraft using it.

I did use a datapack with custom villager trades to get the beacon in my realm.

I used a wither skeleton head dropper datapack in my single player world.

Edit: Here are some screenshots:

I don't understand why it does not work. Unless its a bad file of something like that.