Matrix field alternative (or easier field grouping)
Depending on the amount of data required (and if it makes logical sense to have the data separate from the entry) I'd probably set this up as a "Contact details" section itself, using the individual matrix fields from your example.

Then if some other entry type needs it, set up an entries field in that entry type, limited to entries in the "contact details" section and limited to the number of contact detail entries you want to show, probably 1 going by your example.

This way you can still have your details grouped (as a separate entry) but it's more compact as a single field rather than a matrix in the fields of the entry you're using the contact details in.

The trade-off is that you need to enter your contact details entry before you try to add it to your "x" entry field.

If it makes no logical sense to have the fields as entirely different sections and your fields are getting cumbersome I think the best way is to put them in a different tab to at least remove the clutter.