To me, it's really not the FA and trading markets that cause concern. Sure, Mancini/Hosmer/Barnhart are all memes by now, but obviously no one thinks that finding different versions of those moves was going to make some huge difference. You're talking like, 300 PAs total.
In terms of mid-season work, he stuck with the old core, in my opinion, as long as he should have, and then sold them off for some pretty solid prospects and watched them all regress almost immediately. When the team become relatively competitive again last year, he went out and got the best hitter acquired on the market, who then was pretty mediocre.
In terms of his big offseason signings, Dansby remains the SS with the most fWAR since the beginning of 2023 of that group that was available. Shota has essentially matched Yamamoto so far this year. Taillon has been worth 2.1 fWAR in 200 innings since we signed him....not great, hardly some disaster. Bellinger was a good signing before 2023, obviously, remains to be seen going forward. Suzuki is probably...on the fence right now, but a lot of that is injury based.
For me, the concern to date isn't his performance in the market, it's that he's had to spread the money so thin to cover so many spots because the player development was frankly garbage for like 5 years there. It's starting to show results (Steele, Hoerner, Brown maybe?), but having to go out and pay market rates as often as we have keeps you from committing $40m/year on a true stud. The current crop is good, according to everyone. But...they haven't shown it yet.