Simmons finished 3rd in baseball in dWAR last year (per BR, haven't checked FG). About as much of a WAR machine as you can be defensively. He sucked in 2020 but a lot of people had off seasons. Good point on Schwindel, never really looked into his numbers to see how sustainable his performance was. I assume flukey but I think he's started the spring continuing to hit well so I felt like there was upside. 39th among dudes with 450+ PAs on Fangraphs. At some point I feel like I was confident the general difference between BR and FG methodology was that BR was more 'what actually happened' and FG was more predictive towards future performance, but I'm rusty and can't really define the difference with confidence at this point. I haven't looked in a while, but I believe what you're referring to is more true with pitching war. BR calculates that based on RA9, while FG is based on the one of the FIP metrics. I believe the difference in their fielding metrics is more nuanced than just runs vs predicted runs.