2022:
-4 DRS
3.1 UZR/150
1 fWAR
If they are signing him, it's to rotate with Arroyo and Story, but Story would be the fulltime SS IMO. Arroyo's 2022 fWAR would be higher if he didn't have to play SS or RF.
Iggy 2022: 1.2 bWAR, 118 G, .498 162 WL%
Arroyo 2022: 0.8 bWAR, 87 G, .499 162 WL%
Per bref, Arroyo and Story offer about the same value.
If they sign someone to backup Arroyo (be primary starter in case of expected Arroyo injury), they would probably be LHB.