size of attributes table is too big

I have a PG (v16) instance which is occupying around 1TB of storage. Out of this, around 350GB is occupied by the table pg_catalog.pg_attribute. 

Why is the catalog table's size so big?

Here are the sizes:

I think this table must have tons of dead tuples. Please suggest to me if we can purge any data/shrink the size of this table.

REgards

Siraj