Headphone amplifier

Heedtheadvice

Looking further online the Liam and Daan phones Amp would seem to fit most of your requirement...   

Except different connectors

.....and not currently available afaics ( new or used!) from UK or Eu suppliers see https://www.zdjoutlet.shop/?ggcid=3150747 ..... Maybe risky?

It also has a push/pull type of balanced output ( rather than the just simple necessary impedance balance for best noise rejection) but very much an overkill for the Verum 2 phones and gives so much output that you would risk hearing damage. This type of output is more suited to insensitive high impedance phones.