When leveling the item the bonuses to elemental damage remain the same going from level zero to one and one to two.
#[Bug] Presently the Multipurpose belt ironically has no purpose in its first and second upgrade
small zinc
simple spire
i honestly thought it was a design choice
flat hollow
Thought it was designed like that since it can give 6 of all 3 (with 6 artifacts). Or 12 at +3. Which can be better than the individual boosters, although more of a pain to organize
small zinc
Why not have it be a two-star item then? If nothing changes, there's no reason for it to have an additional upgrade.
If something else changes, it should be represented on the item.
west oxide
Generally, not all values change when levels change. As you mentioned, the Multipurpose Belt has different elemental damage types, so typically only one type is used, but the overall increase is significant, so there are intermediate levels where values do not change. We will consider how to represent artifacts with large minimum increases per level so that they are not perceived as bugs.