Low pressure on the hot water tap

Hi if it's only that tap on the hot and all other tap outlets throughout the house are fine sounds like a problem with the actual tap head on the hot side. Depending on the type of tap u have

You do not say if this is a new problem also how is the water heated ie combi boiler or gravity fed from loft tank

I would replace the valve body as they tend to wear out after a while, usually a simple cheap fix..... usually.

If all other tapes are working fine then I would Recommend replacing the tapes. If not then it could be something wrong with the boiler and would need Further investigation.