Building a bullpen is harder than just throwing money at it. Very few relievers are good year in and year out. Your top 5 RP free agents coming out of last year were:
Edwin Diaz, signed for $20M per. Will miss the season
Kenley Jansen, signed $16M per. 4.26 ERA, 3.30 FIP so far
Aroldis Chapman, signed $3.8 per. 3.24 ERA, 2.04 FIP so far. Having his best season since 2017, but has major character issues
Craig Kimbrel, signed $10M per. 6.60 ERA, 4.50 FIP so far
Taylor Rodgers, signed $11M per. 4.73 ERA, 6.08 FIP.
Who else would you have had them signing? I would have liked to see an addition in the offseason as well, but it's not as easy as tossing money at.