Netherite is considered Common

The Rarity of Netherite is common. This means that, for example, an Oak Log and a Netherite Block have the same rarity.

This is inconsistent with the criteria stated in the 24w33a changelog: 

Items and blocks become more rare depending on the following factors:

The chance of finding it in a loot table, including mob drops
The amount of travelling required to obtain it
The difficulty of any obstacle which must be overcome to obtain it
The possible amount of that item or block which exists in the world

 Netherite matches all criteria.

Additionally, also in the 24w33a changelog:

Any item or block that can be crafted must inherit the highest rarity of its crafting ingredients

Since netherite upgrades are uncommon rarity, all netherite items must be uncommon.