I can still defend IKF. I'll do anything for Ross. Here is the case for Falaffle:
IKF @ 3B
1207 career innings (154 games), +19 DRS, +6.7 UZR, +22 OAA
Gio @ 3B
4620 career innings (585 games), +10 DRS, +13.5 UZR (+3.9 UZR/150), -18 OAA
Despite Gio Urshela being a native 3B with a good reputation, the difference in defensive talent might be massive. It could be as much as 10 runs or one full win over a complete MLB season. Keep in mind that these numbers are cumulative, so in one season of data IKF according to DRS has more defensive runs saved than Gio has done in nearly 4x the games. OAA agreeing with DRS is helpful for confidence in IKF's defense. OAA hating Urshela is interesting.
Other factors:
Career BsR, 0.1 for IKF and -23.4 for Gio
Age: 28 y 10m for IKF vs 32 y 4m for Gio
Career walk and K rates: slight edge for IKF
2023 maxEV: 106.1 for Gio, 109.6 for IKF
2023 xwOBA: .288 for Gio and .292 for IKF
2023 hard hit rate: much higher for IKF
Of course, Urshela does have better 2024 projections and has hit for much more power in his career.
That being said, it seems like a reasonable prospect that Gio Urshela is just completely cooked as an old, slow, fat 3B with declining defense (that OAA has never liked) and power that dried up completely in 2023.
IKF on the other hand is young, agile, fertile, flexing his muscles, hitting for more power, discovering how to barrel the ball, blossoming into a divine lotus of limitless defensive prowess at his new fulltime position of third base. His upside is palpable. He's a throbbing vessel of flesh and talent, waiting to escape the soul-sucking curses of New York. He's been focusing on yanking barrels in the air all offseason and he is ready to unlock his Bregman-eqsue potential. In three months you will be thanking Ross for GETTING that second year of control.