Ruiz isn't Machado or Arenado; but he's above average defensively at 3rd. Easily better than Alberto. (Though I do think Alberto was better at 3rd vs. 2nd.)
According to stat cast Alberto was +6 at second base.
Trey Mancini and Chris Davis were an even 0 at 1B.
Villar was -12, Martin was -5.
So yeah I think Iglesias is a big upgrade.
I trust these numbers much more than the other infield defense metrics. They’re actually using live data like sprint speed and positioning rather than just zones where that position would normally be.