The Luis Arraez/Pablo Lopez comparison is a case of Arraez pitching into some great luck while Lopez has been unlucky to this point.
Luis Arraez is a career .328 hitter with a career .299 xBA (a difference of .029 points). However, this year, his batting average is .055 points higher than his xBA (.388 to .333). The last time I checked, Zips projected that he'll end the year with a ~.360 batting average. I think that there is a lot of negative regression to the mean that will happen, and Arraez does not walk nearly enough to continue batting close to .400 (Rod Carew walked 10% of the time in 1977 and Ted Williams walked 21.6% of the time in 1942. Luis Arraez "only" has a 7% walk rate).
Conversely, Pablo Lopez has hit into some poor luck. From 2020-2022, he's posted a 3.52 ERA and 3.58 xERA over 340.0 IP (with him posting equivalent 3.75 figures in 2022). This year, his 3.03 xERA is paired with a much higher 3.89 figure in the first half. Hitters are slashing .220/.281/.358 against him (a heck of a lot worse than Gallo and Kepler, two guys who half of y'all want to DFA), and he's probably going to strikeout 250 batters if he stays healthy.
They both have equivalent trade values (per BTV), and I am very excited to see Lopez, Ryan, and Ober form a three-headed monster at the top of the rotation for the next 4+ years.