While there were no belts in BG3 EA, the belt slot was there. Belts in BG3 were intended to function similar to ring and amulets, in that they have no visuals.
Belts are also a pretty important part of DnD, so it is a bit unusual for BG3 to not have them.
Belt of Giant Strength, for example, is very iconic piece of DnD equipment.
Or the Blessed Belt of Transgenderism - present in e.g. in BG1 or the OotS comic.
