Honestly the UI just needs to be standardized for the pages dealing with Contacts, here’s some priority-ordered suggestions. Standard table components with hideable columns & user-selectable filters & sorts are widely available, it’d make things much easier if the table views used something like that.
Single-Contact view: show Created At & datetime timezone
/contacts/{id}/details
already shows Last Updated but timezone is unclear
Created At is available via API, just needs display
Segments view: add filters, columns, actions, & pagination
/contacts/segments/{id}
add filters for Last Updated & Subscribed
add Subscribed column
add Download action
add pagination
