Vox is a far-right party, and I don't think they would even overly dissent from that categorisation.
Right, whereas PAN is supposed to be a moderate center-right party. Vox admits that it appeals to maybe 15-20% of voters at the absolute maximum and is mostly interested in pressuring other, more center-right to centrist parties to adopt right-wing policies than it is in achieving majority support for itself. That's a perfectly viable and reasonable electoral strategy for a party on the fringe in a party and electoral system like Spain's. PAN is the exact opposite, at least in theory; it's supposed to be one of the center-right to centrist parties that actually can sometimes achieve a majority or near-majority support for itself. However, it is obviously failing at doing so and falling into a trap of being too narrow ideologically to win elections.
