Call me a Finnegan moderate. He's an ERA beats his FIP guy every year, especially the last 2, so natch that fWAR might have it in for him a bit. 2022 probably was his best year in terms of run prevention, Ks, and BBs, when he only closed after the trade deadline. He gets ground balls well above average, his launch angle is low, so he's not killed by hard hit rate and HRs. He's just going to occasionally give up the crushing homer. I prefer him with clean innings when the homer is less likely to kill you, and he needs to limit his walks.
Slate is right about 1st half / 2d half last year. 1st half, he was a legit all star. 2nd half, overwhelmingly poor performance. You can't dress up an 11/18 BB/K ratio in 23 innings and say that's good for a guy who gets into trouble when he walks people. ERA jumped from 2.45 to 5.79. Opponents went from .190 / .255 / .340 to .337 / .404 / .490. Think about that .894 OPS in the second half. Damage would have been worse but for a slight drop in FB% and HR/FB.
Assuming that 2nd half was an aberration, he can close and rack up effective outings when used right on a bad team. I just don't see him as a fireman in the middle of innings with men on. Trading him now probably is at a depressed price. Maybe you roll the dice and hope he rebuilds value for next year's deadline, but he may end up closer to Jacob Barnes than a top 10 closer notwithstanding his save count.